Heat treatment apparatus using a lamp for rapidly and uniformly heating a wafer

ABSTRACT

A heat treatment apparatus enables a rapid temperature rise of an object to be processed while giving an excellent economical efficiency. A heating unit heats an object to be heated by irradiating a light onto the object. A plurality of lamps are provided in a lamp house. The lamps include at least one first lamp and a plurality of second lamps each having an irradiation area smaller than that of the first lamp. The lamp house has a first lamp accommodation part at a center thereof and a second lamp accommodation part surrounding the first lamp accommodation part so that the first lamp accommodation part accommodates the first lamp and the second lamp accommodation part accommodates the second lamps.

This application is a divisional application of U.S. patent applicationSer. No. 10/085,092, filed on Mar. 1, 2002, now U.S. Pat. No. 7,075,037the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to heat treatment apparatusesand more particularly to a heat treatment apparatus which performs ananneal process or a chemical vapor deposition (CVD) process by heatingan object to be processed, such as a single crystalline substrate or aglass substrate, with a lamp and a quartz window used for such a heattreatment apparatus. The present invention is suitable for a rapidthermal processing (RTP: Rapid Thermal Processing) used formanufacturing semiconductor devices, such as a memory or an integratedcircuit (IC). The rapid thermal processing (RTP) includes rapid thermalannealing (RTA), rapid thermal cleaning (RTC), rapid thermal chemicalvapor deposition (RTCVD), rapid thermal oxidization (RTO) and rapidthermal nitriding (RTN).

2. Description of the Related Art

Generally, in order to manufacture a semiconductor integrated circuit,various kinds of heat treatment, such as a film deposition process, ananneal process, an oxidization diffusion process, a sputtering process,an etching process and a nitriding processing may be repeatedlyperformed on a silicon substrate such as a semiconductor wafer aplurality of times.

Since yield rate and quality of semiconductor manufacturing processescan be improved, the RTP technology to rise and drop the temperature ofthe wafer (object to he processed) has attracted attention. Aconventional RTP apparatus generally comprises: a single-wafer chamber(process chamber) for accommodating an object to be processed (forexample, a semiconductor wafer, a glass substrate for photograph masks,a glass substrate for a liquid-crystal display or a substrate foroptical discs); a reflector (reflective board) arranged at the oppositeside of the object to be processed with respect to a quartz windowarranged in the interior of the process chamber; and a heating lamp (forexample, halogen lamp) arranged at an upper part or above the quartzwindow, and the lamp.

The reflector is made of aluminum, and gold plating is given to areflective part thereof. A cooling mechanism such as a cooling pipe isprovided so as to prevent temperature breakage of the reflector (forexample, exfoliation of gold plating due to a high temperature). Thecooling mechanism is provided so as to prevent the reflector from beingan obstacle of cooling the object to be processed at the time ofcooling. The rapid temperature rising demanded for the RTP technology isdependent on the directivity of the optical irradiation to the object tobe processed and the power density of the lamp.

The quartz window may be in the shape of a board, or can be in the formof tube which can accommodate the object to be processed. Whenmaintaining a negative pressure environment in the process chamber byevacuating gasses in the process chamber by a vacuum pump, a thicknessof the quartz window is set to, for example, about 30 to 40 mm so as tomaintain the pressure difference between the internal pressure and theatmospheric pressure. The quartz window may be formed in a curved shapehaving a reduced thickness so as to prevent generation of a thermalstress due to temperature difference generated by a temperature rise.

A plurality of halogen lamps are arranged so as to uniformly heat theobject to be processed. The reflector reflects the infrared raysirradiated from the halogen lamps toward the object to be processed. Theprocess chamber is typically provided with a gate valve on a sidewallthereof so as to carry in and out the object to be processed. Moreover,a gas supply nozzle, which introduces a process gas used for heattreatment, is connected to the sidewall of the process chamber.

The temperature of the object to be processed affects the quality ofprocess such as, for example, a thickness of a film in a film depositionprocess, etc. For this reason, it is necessary to know the correcttemperature of the object to be processed. In order to attain high-speedheating and high-speed cooling, a temperature measuring device whichmeasures the temperature of the object to be processed is provided inthe process chamber. The temperature measuring device may be constitutedby a thermocouple. However, since it is necessary to bring thethermocouple into contact with the object to be processed, there is apossibility that the processed body is polluted with the metal whichconstitutes the thermocouple. Therefore, there is proposed a payro meteras a temperature measuring device which detects an infrared intensityemitted and computes a temperature of an object to be processed from theback side thereof based on the detected infrared intensity. The payrometer computes the temperature of the object to be processed by carryingout a temperature conversion by an emissivity of the object to beprocessed according to the following expression:E _(m)(T)=εE _(BB)(T)  (1)where, E_(BB)(T) expresses a radiation intensity from a black bodyhaving the temperature T; E_(m)(T) expresses a radiation intensitymeasured from the object to be processed having the temperature T; εexpresses a rate of radiation of the object to be processed.

In operation, the object to be processed is introduced into the processchamber through the gate valve. The peripheral portion of the object tobe processed is supported by a holder. At the time of heat treatment,process gases such as nitrogen gas and oxygen gas, are introduced intothe process chamber through the gas supply nozzle. On the other hand,the infrared ray irradiated from the halogen lamps is absorbed by theobject to be processed, thereby, rising the temperature of the object tobe processed.

Recently, a demand for a rapid temperature rise of RTP has beenincreased so as to achieve a high-quality process of an object to beprocessed and improve a throughput. For example, there is a demand forincreasing a temperature rising rate from 90 degrees/sec to 250degrees/sec.

A support ring on which an object to be processed such as a siliconesubstrate is placed is formed of ceramics (for example, SiC) havingexcellent heat resistance. There is a difference in heat capacitybetween the support ring and the silicon substrate, which results in adifference in temperature rise. For this reason, the temperature risingrate of a periphery of the object to be processed, which peripherycontact with the support ring, is smaller than that of the center of theobject to be processed. Thus, there is a problem in that it is difficultto carry out a rapid and uniform temperature rise over the entiresurface of the object to be processed. As measures for solving such aproblem, the present inventors made a study on heating the periphery ofthe object to be processed by a larger power than that applied to thecenter of the object. Additionally, the reflector also deteriorates dueto heating with a large power. However, a high-output lamp has a servicelife shorter than a low-output lamp. Similarly, the reflector forhigh-output lamps also has a service life shorter than the reflector forlow-output lamps. Consequently, in order to exchange the life-expiredlamps and reflectors located in the periphery of a lamp house, the wholelamp house including the lamps and reflectors located in the center ofthe lamp house, which are still usable, must be exchangedsimultaneously, which results in uneconomical operation.

A rapid temperature rise depends on a power density of a lamp and adirectivity of the optical irradiation from the lamp to an object to beprocessed. In the case of a single end lamp 2, which has only oneelectrode part 3 like the conventional lamp, an illuminant (coil 4 inthe figure) of the lamp 2 is perpendicularly formed to the object to beprocessed, as shown in FIG. 1. Here, FIG. 1 is an illustrativecross-sectional view showing the shape of the conventional lamp. Sincethe coil 4 projects a light in a direction perpendicular to the axialcenter of the coil 4 concerned, it is impossible for the lamp 2 alone tocontrol the directivity. Conventionally, The directivity of the lamp 2is obtained by providing a cylindrical reflector 5 or reflective filmaround the lamp 2 so as to cover the lamp 2. However, the reflector 5and the reflective film cannot reflect light 100%. Therefore, the lightis absorbed or diffused to some extent, and there is a problem in thatthe energy of the lamp light decreases. Since the reflection takes placea plurality of times at the reflector 5 and the reflective surface, thepower density of the light irradiated onto the object to be processedmay become less than one half of the light at the time of projection. Onthe other hand, it can be considered to increase the density of powerreaching the object to be processed by increasing the electric powersupplied to the lamp 2. However, such an approach causes an increase inthe power consumption, which is not economically preferable. Therefore,conventionally, even if the energy of the lamp light decreases, thereflector 5 or the reflective film had to be used so as to obtain adesired directivity of the lamp 2.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide an improvedand useful heat treatment apparatus in which the above-mentionedproblems are eliminated.

A more specific object of the present invention is to provide a heatingunit, a heat treatment apparatus and a lamp used as a heat source of theheat treatment apparatus, which enable a rapid temperature rise of anobject to be processed while giving an excellent economical efficiency.

Another object of the present invention is to provide areflector-equipped lamp, which can project a light emitted by anilluminant preferably within one reflection so as to improve adirectivity and power density of the projected light.

A further object of the present invention is to provide a lamp having anexcellent directivity without a reflector.

In order to achieve the above-mentioned objects, there is providedaccording to one aspect of the present invention a heating unit forheating an object to be heated by irradiating a light onto the object,the heating unit comprising: a plurality of lamps including at least onefirst lamp and a plurality of second lamps each having an irradiationarea smaller than that of the first lamp; and a lamp house having afirst lamp accommodation part at a center thereof and a second lampaccommodation part surrounding the first lamp accommodation part so thatthe first lamp accommodation part accommodates the first lamp and thesecond lamp accommodation part accommodates the second lamps.

In the heating unit according to the above-mentioned invention, each ofthe second lamps generates an irradiation energy per unit length greaterthan an irradiation energy per unit length of the first lamp. A numberof the second lamps per unit area may be greater than a number of thefirst lamps per unit area. The lamps may be detachably attached to thefirst and second lamp accommodating parts, respectively. Each of thelamps may have a reflective part that reflects a light emitted by anilluminant thereof. Each of the lamps may have a threaded part on a sidesurface thereof, and each of the first and second lamp accommodationparts may have a threaded part engageable with the treaded part of eachof the lamps. Each of the first and second lamp accommodation parts mayhave a plurality of plates attached to an inner surface thereof so thatthe plates are located between the inner surface and each of the lamps,thereby holding each of the lamps by elastic deformation of the plates.

Additionally, there is provided according to another aspect of thepresent invention a heat treatment apparatus for applying a heattreatment to an object to be processed, the heat treatment apparatuscomprising: a support member on which the object to be processed isplaced; and a heating unit located above the support member so as toirradiate a light onto the object to be processed placed on the supportmember, wherein the heating unit comprising: a plurality of lampsincluding at least one first lamp and a plurality of second lamps eachhaving an irradiation area smaller than that of the first lamp; and alamp house having a first lamp accommodation part at a center thereofand a second lamp accommodation part surrounding the first lampaccommodation part so that the first lamp accommodation partaccommodates the first lamp and the second lamp accommodation partaccommodates the second lamps.

According to the above-mentioned invention, the first lamp having alarge irradiation area is located in the center of the lamp house andthe second lamps having a smaller irradiation area than the first lampare located around the first lamp. Therefore, the central part of theobject to be processed can be irradiated with a large irradiation area,and the periphery of the object to be processed can be irradiated with asmall irradiation area. Moreover, the irradiation energy per unit areaof the second lamps can also be raised. Thereby, the periphery of theobject to be processed can be heated intensively. Moreover, such anaction will become more remarkable by making the number of the firstlamps per unit area greater than the number of second lamps per unitarea. Furthermore, only a degraded lamp can be easily removed andreplaced with a new one by making the lamps individually detachable fromthe lamp support part. That is, there is no need to remove the lampsthat are still usable. Moreover, there is no need to replace a wholelamp support part, and only a degraded lamp can be replaced.

Moreover, the heat treatment apparatus according to the above-mentionedinvention has the heating unit mentioned above, and, therefore, providesthe same effects. Specifically, a narrow area of the periphery of theobject to be processed, which area contacts a support ring and has a lowtemperature rise rate, can be efficiently irradiated by the secondlamps. Moreover, the center and periphery of the object to be processedcan be uniformly heated by increasing the irradiation energy of thesecond lamps or increasing the number of the second lamps per unit area.Furthermore, only a degraded lamp can be easily removed and replacedwith a new one by making the lamps individually detachable from the lampsupport part. That is, there is no need to remove the lamps that arestill usable. Moreover, there is no need to replace a whole lamp supportpart, and only a degraded lamp can be replaced. Accordingly, ahigh-quality heat treatment can be applied to the object to beprocessed, and a high-quality object can be produced. Therefore, themaintenanceability of the heat treatment apparatus can be improved.

Additionally, there is provided according to another aspect of thepresent invention a lamp applicable to a heat source for heating anobject to be processed, the lamp comprising: an electrode part to whichan electric power is supplied; a pair of first filaments connected tothe electrode part; a second filament connected to the first filamentsand having a diameter smaller than a diameter of each of the firstfilaments, wherein the second filament is configured and arranged toserve as a surface illuminant with respect to the object to beprocessed.

In the lamp according to the above-mentioned invention, the surfaceilluminant may be parallel to the object to be processed. The surfaceilluminant may have a convex shape protruding in a direction away fromthe object to be processed. The surface illuminant may have a polygonalshape or a circular shape when viewed from the object to be processed.The lamp according to the present invention may further comprise ashield part that reflects a light emitted by the second filament, theshield part being located on a side opposite to the object to beprocessed with respect to the second filament. The second filament mayinclude a first part facing the object to be processed and a second partfarther from the object to be processed than the first part, and thefirst part may have a work function lower than a work function of thesecond part. The first part may have a cover film made of a materialhaving a work function lower than a work function of a material of thesecond filament. The second filament may be made of tungsten, and thecover film is made of thorium. The second filament may be made of amaterial selected from a group consisting of platinum, connel alloy,tungsten and nickel, and the cover film is made of a material selectedfrom a group consisting of barium oxide, strontium oxide and calciumoxide.

Additionally, there is provided according to another aspect of thepresent invention a heat treatment apparatus for applying a heattreatment to an object to be processed, the heat treatment apparatuscomprising: a support member on which the object to be processed isplaced; and a plurality of lamps located above the support member forheating the object to be processed, each of the lamps comprising: anelectrode part to which an electric power is supplied; a pair of firstfilaments connected to the electrode part; a second filament connectedto the first filaments and having a diameter smaller than a diameter ofeach of the first filaments, wherein the second filament is configuredand arranged to serve as a surface illuminant with respect to the objectto be processed.

According to the above-mentioned invention, when an electrical power issupplied to the first and second filaments from the electrode part, anamount of heat generated per unit length of the second filament islarger than the first filament. Therefore, the second filament emitslight earlier than a first filament. Moreover, since the amount of heatgenerated per unit length of the first filaments and the second filamentdiffer from each other, only the second filament can emit a light.Therefore, only the second filament can be made to emit a light with asmaller electric power than a conventional lamp in which the first andsecond filaments are formed a wire having the same diameter.

Furthermore, the second filament serves as an illuminant having a largearea by arranging the second filament in the form of a surface. Whensuch a lamp is seen from the projection face at the time of luminescenceof the lamp, the illuminant can be regarded as a surface illuminant.Moreover, the light projected from the side which faces the object to beprocessed is directly irradiated onto the object to be processed.Moreover, when a plurality of filament coils are provided in the lamp,the light projected from one coil overlaps with the light projected fromthe adjacent coils, which increases an energy projected from the lamp.With this state, the light projected from the lamp provides a sufficientdirectivity. Therefore, reflective means such as a reflector forobtaining a good directivity, is not needed. Such a surface illuminantcan be achieved by forming the second filament by a plurality of coilsarranged in parallel or in series.

Moreover, the shield part shields the light traveling in a directionopposite to the object to be processed, and contributes to convert thelight into a light-emitting energy. Moreover, since the first part ofthe second filament tends to emit light easily, only the first part towhich a thorium film having a low work function is applied emits a lightwhen an electric power is applied to the second filament. Therefore, inthe lamp according to the present invention, the supplied energycontributes only to luminescence of the first part. Therefore, 100% ofthe supplied energy can be used only for a light-emitting energyprojected from the first part. Therefore, a light having a high energycan be irradiated onto the object to be processed.

Additionally, there is provided according to another aspect of thepresent invention a lamp adapted to be used as a heat source for heatingan object to be heated, the lamp comprising: an illuminant generating alight; a light-emitting part having an inner surface covering theilluminant and an projection face through which the light generated bythe illuminant is projected, the inner surface having a hemisphericalshape or a circular cone shape; and a reflective part provided to theinner surface of the light-emitting part so as to reflect the lightgenerated and emitted by the illuminant.

In the lamp according to the above-mentioned invention, the illuminantmay be positioned so as to emit the light to travel in a directionperpendicular to the projection face. The lamp according to the presentinvention may further comprise an electrode part to which an electricpower is supplied and connected to the light-emitting part, wherein theilluminant comprises a filament coil electrically connected to theelectrode part and the filament coil is positioned parallel to theprojection face. Additionally, the illuminant may be configured andarranged to be a surface light-source when the lamp is viewed in adirection perpendicular to the projection face. The reflective part mayinclude a reflective film provided on the inner surface of thelight-emitting part. The reflective film may be made of a plated goldfilm.

Additionally, there is provided according to another aspect of thepresent invention a heat treatment apparatus for applying a heattreatment to an object to be processed, the heat treatment apparatuscomprising: a support member on which the object to be processed isplaced; and a plurality of lamps located above the support member forheating the object to be processed, each of the lamps comprising: anilluminant generating a light; a light-emitting part having an innersurface covering the illuminant and an projection face through which thelight generated by the illuminant is projected, the inner surface havinga hemispherical shape or a circular cone shape; and a reflective partprovided to the inner surface of the light-emitting part so as toreflect the light generated and emitted by the illuminant.

According to the above-mentioned invention, the lamp can efficientlyproject a light emitted by the illuminant with a single reflection bythe reflective part, which is provided to the inner surface formed in ahemisphere or a circular cone configuration. Moreover, the configurationof the inner surface and the reflective part act to converge the lightemitted by the illuminant, which improves the directivity of the lamp.Furthermore, the light emitted by the illuminant travels in a directionperpendicular to the object to be processed. That is, the lighttraveling toward the object to be processed is directly irradiated ontothe object to be processed, and other lights travels toward thereflective part.

The configuration of the reflective part is the same as the innersurface of the light-emitting part, and the reflective part efficientlyreflects the light toward the object to be processed preferably with onetime reflection. Therefore, the light emitted by the illuminant can beirradiated onto the object to be processed with no reflection or onetime reflection. That is, since the lamp according to the presentinvention has less number of times of reflection by the reflective partthan the conventional lamp, the light projected through the projectionface is has less energy loss and excellent in directivity.

In addition, it is possible to reduce a reflective loss by providing ahigh reflectance film, such as a plated gold film, on the lightreflecting surface of the reflective part. Such a structure raises theprojection energy of the lamp and enables power-saving of the lamp.Furthermore, the projection energy of the lamp can be raised since theilluminant of the lamp has the configuration regarded as a surfaceilluminant, which can be achieved by arranging a plurality of filamentcoils in parallel.

The heat treatment apparatus according to the above-mentioned inventionhas the same effect as the above-mentioned lamp, and facilitates a rapidtemperature rise of the object to be processed. Therefore, since theheat treatment apparatus according to the present invention is excellentin the energy efficiency and directivity of the lamp, the irradiationefficiency can be improved and a rapid temperature rise can be attainedwith a low power consumption.

Additionally, there is provided according to another aspect of thepresent invention a lamp for heating an object to be processed, the lampbeing configured and arranged to be supported and cooled by a lampsupport part, the lamp comprising: a light-emitting part emitting alight so as to heat the object to be processed; and a reflectorreflecting the light emitted by the light-emitting part toward theobject to be processed, wherein the light-emitting part and thereflector are detachably attached to the lamp support part.

In the lamp according to the above-mentioned invention, the reflectormay be configured and arranged to be attached to the lamp support partand separable from the light-emitting part. The reflector may have ahemispherical shape or a circular cone shape. The reflector may comprisean aluminum body and a reflective film formed on a surface facing thelight-emitting part, the reflective film including a nickel layer and agold layer or a nickel layer, a gold layer, a rhodium layer and a goldlayer provided on the surface of the aluminum body sequentially in thatorder. The reflector may be configured to reflect an infrared light anda visible light.

Additionally, there is provided according to another aspect of thepresent invention a heat treatment apparatus for applying a heattreatment to an object to be processed, the heat treatment apparatuscomprising: a support member on which the object to be processed isplaced; a lamp support part located above the support member; and a lampattached to the lamp support part for heating the object to beprocessed, the lamp comprising: a light-emitting part emitting a lightso as to heat the object to be processed; and a reflector reflecting thelight emitted by the light-emitting part toward the object to beprocessed, wherein the light-emitting part and the reflector aredetachably attached to the lamp support part.

In the heat treatment apparatus according to the above-mentionedinvention, the reflector may be configured and arranged to be attachedto the lamp support part and separable from the light-emitting part. Thereflector may have a hemispherical shape or a circular cone shape. Theheat treatment apparatus according to the present invention may furthercomprise an electrode part to which an electric power is supplied andconnected to the light-emitting part, wherein the lamp support partcomprises: a first cooling part for cooling the reflector and thelight-emitting part; and a second cooling part for cooling the electrodepart. The heat treatment apparatus according to the present inventionmay further comprise an electrode part to which an electric power issupplied and connected to the light-emitting part, wherein the electricpower supplied to the electrode part differs depending on positionscorresponding to the object to be processed. The light-emitting part mayhave reflecting means for reflecting the light toward the object to beprocessed. The reflector and the reflecting means together may form ahemispheric shape of a circular cone shape.

According to the above-mentioned invention, the light-emitting part andthe reflector is individually and detachably attached to the lampsupport part. Thus, only the light-emitting part and the reflector thatare degraded can be easily replaced. Further, there is no need toreplace the entire lamp support part, which includes usablelight-emitting parts and usable reflectors, when replacing a degradedlight-emitting part or a degraded reflector, which provides an economicway. Moreover, since the light-emitting part and the reflector areindividually replaceable, the replacement work is not complicated.

The heat treatment apparatus according to the above-mentioned inventionhas the lamp mentioned above, and provides the same effects.Furthermore, the heat treatment apparatus according to the presentinvention has the first cooling part, which cools the light-emittingpart and the reflector, and the second cooling part, which cools theelectrode part to which an electric power is supplied. For this reason,the light-emitting part and the reflector, and the electrode part can beindividually cooled at their optimal temperatures. Therefore,degradation of the light-emitting part and the reflector, or theelectrode part can be prevented effectively.

Moreover, for example, it is possible to supply a larger electric powerto the electrode part connected to the light-emitting part correspondingto the periphery (part into which temperature cannot rise easily) of theobject to be processed than the electrode part connected to thelight-emitting part corresponding to the central part of the object tobe processed. In addition, although the light-emitting part and thereflector of a high output may have a shorter service-life than thelight-emitting part and the reflector of a low output, thelight-emitting part and the reflector can be individually replaced bybeing detached from the lamp support part.

Other objects, features and advantages of the present invention willbecome more apparent from the following detailed description when readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing a configuration of a conventionallamp;

FIG. 2 is a cross-sectional view of a heat treatment apparatus accordingto a first embodiment of the present invention;

FIG. 3 is a bottom plan view of a window which is a variation of awindow shown in FIG. 2;

FIG. 4 is an enlarged cross-sectional view of a part of the window shownFIG. 3;

FIG. 5 is an enlarged cross-sectional view of a part of a window whichis another variation of the window shown in FIG. 2;

FIG. 6 is an illustrative bottom plan view of a heating unit shown inFIG. 2;

FIG. 7 is an enlarged cross-sectional view showing a part of the heatingunit shown in FIG. 6;

FIG. 8 is a view corresponding to FIG. 7 when lamps are removed from theheating unit shown in FIG. 6;

FIG. 9 is an illustrative cross-sectional view of a lamp shown in FIG.7;

FIG. 10 is an illustrative cross-sectional view of the lamp shown inFIG. 7;

FIG. 11 is an illustrative bottom plan view of the lamp shown in FIG. 7;

FIG. 12 is an illustrative side view of the lamp indicating optical pathof a light emitted from a filament;

FIG. 13 is another illustrative side view of the lamp indicating opticalpath of a light emitted from the filament;

FIG. 14 is an illustrative bottom plan view of a lamp 130A which is avariation of the lamp shown in FIG. 7;

FIG. 15 shows a filament arranged so that a plurality of coils crosseach other

FIG. 16 shows a filament which has a coil formed with a large width;

FIG. 17 is an illustrative bottom plan view of a filament in which acoil forms a spiral

FIG. 18 is an illustrative side view of the filament shown in FIG. 17;

FIG. 19 is an enlarged cross-sectional view of a part of a lamp supportpart shown in FIG. 7 when the lamp is not expanded;

FIG. 20 is an illustrative cross-sectional view of a lamp support partof the heating unit shown in FIG. 6;

FIG. 21 is an illustrative bottom plan view of the lamp support part ofthe heating unit shown in FIG. 6;

FIG. 22 is an illustration of lights irradiated by the lamps of theheating unit shown in FIG. 2 onto the object to be processed;

FIG. 23 is an illustration of lights irradiated by the lamps of theheating unit shown in FIG. 2 onto the object to be processed;

FIG. 24 is an illustrative cross-sectional view showing a variation ofan arrangement of the lamps shown in FIG. 7;

FIG. 25 is a flowchart of an operation to drive the lamps;

FIG. 26 is a flowchart of a control operation for cooling the lamps;

FIG. 27 is a cross-sectional view of a heating unit provided in a heattreatment apparatus according to a second embodiment of the presentinvention;

FIG. 28 is an illustrative cross-sectional view of a lamp provided inthe heating unit shown in FIG. 27;

FIG. 29 is an enlarged cross-sectional view of a reflector attached tothe lamp shown in FIG. 28;

FIG. 30 is a bottom view of the reflector shown in FIG. 29;

FIG. 31 is a cross-sectional view of a reflector which is a variation ofthe reflector shown in FIG. 29;

FIG. 32 is a plan view of the reflector shown in FIG. 31;

FIG. 33 is an illustrative enlarged cross-sectional view of a radiationthermometer and parts of the process chamber in the vicinity of theradiation thermometer;

FIG. 34 is an illustrative enlarged cross-sectional view of a sensor rodand a part of the radiation thermometer in the vicinity of the sensorrod;

FIG. 35 is a graph showing a relationship between emissivity of a quartzboard and wavelength of a radiation light;

FIG. 36 is a graph showing a relationship between emissivity of asilicon carbide (SiC) board and wavelength of a radiation light;

FIG. 37 is a graph showing a relationship between emissivity of analuminum nitride (AlN) board and wavelength of a radiation light;

FIG. 38 is an illustrative side view of a radiation-thermometer which isa variation of the radiation thermometer shown in FIG. 2;

FIG. 39 is an illustrative bottom view of a heating unit provided in aheat treatment apparatus according to a third embodiment of the presentinvention;

FIG. 40 is an enlarged cross-sectional view of a part of the heatingunit show in FIG. 39;

FIG. 41 is an illustrative cross-sectional view of a lamp shown in FIG.40;

FIG. 42 is an illustrative bottom view of the lamp shown in FIG. 41.

FIG. 43 is a an illustrative side view of a lower part of the lamp shownin FIG. 41;

FIG. 44 is a circuit diagram of filament coils shown in FIG. 41;

FIG. 45 is a circuit diagram of the filament coils in differentarrangement;

FIG. 46 is an illustration of a variation of the filament coils shown inFIG. 43; and

FIG. 47 is an illustration of another variation of the filament coilsshown in FIG. 43.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

A description will now be given of a first embodiment of the presentinvention. FIG. 2 is a cross-sectional view of a heat treatmentapparatus according to the first embodiment of the present invention.

As shown in FIG. 2, the heat treatment apparatus 100 generally comprisesa process chamber 110, a quartz window (light-transmitting window) 120,a heating unit 140, a support ring 150, a gearing 160, a permanentmagnet 170 a gas introducing part 180, an exhausting part 190, aradiation thermometer 200 and a control part 300. It should be notedthat the heating unit 140 and lamps provided in the heating unit 140 areillustrated in simplified forms.

The process chamber 110 is formed of stainless steel or aluminum. Thequartz window 120 is connected to a top of the process chamber 110. Thesidewall of the process chamber 110 and the quartz window 12 define aprocess space in which an object W to be processed (semiconductor wafer:hereinafter referred to as a wafer W) is subjected to a heat treatment.The support ring 150 on which the wafer W is placed and a support part152 connected to the support ring 150 are arranged in the process space.The process space is maintained to be a predetermined negative pressureby the exhaust part 190. The wafer W is carried in or out from theprocess chamber 110 through a gate valve (not shown in the figure)provided to the sidewall of the process chamber 110.

A bottom part 114 of the process chamber 110 is connected to a coolingpipes 116 a and 116 b (hereinafter simply referred to as cooling pipe116) so that the bottom part 114 serves as a cooling plate. Ifnecessary, the cooling plate 114 may be provided with a temperaturecontrol arrangement. The temperature control arrangement may comprise acontrol part 300, a temperature sensor and a heater. A cooling water issupplied to the temperature control arrangement from a water supplysource such as a water line. A coolant such as alcohol, gurden or flonmay be used instead of the cooling water. As for the temperature sensor,a known sensor such as a PTC thermister, an infrared sensor, athermocouple, etc. may be used. The heater can be a line heater wound onthe outer surface of cooling pipe 116. The temperature of the coolingwater flowing through the cooling pipe 116 can be adjusted bycontrolling an electric current flowing through the line heater.

The quartz window 120 is attached to the process chamber in an airtightmanner so as to maintain the negative pressure environment inside theprocess chamber 110 and transmit a heat radiation light emitted from thelamps of the heating unit 140. The window 120 is formed of transparentceramics in the form of a cylindrical plate 121 having a diameter ofabout 400 mm and a thickness ranging from of 5 mm to 10 mm, for example,5 mm. In the present embodiment, the transparent ceramics forming theplate 121 is not limited to but Al₂O₃.

Ceramics is a polycrystalline substance obtained by sintering araw-material powder. Generally, the fine structure of the ceramicsconsists of precipitates and a pores (holes) besides crystal grains andgrain boundaries. Although the ceramics is opaque fundamentally, atransparent ceramics can be made by changing the fine structure bycontrolling the sintering process, the raw-material powder andadditives. Generally, the transparent ceramics is referred to as atranslucent ceramics. Pores, precipitates, etc. hardly exist in the finestructure of the translucent ceramics which consists of grain boundariesonly. Thereby, a light passing through inside the translucent ceramicshas almost no loss of energy due to substances, and is capable ofpassing through the material without being diffused, which providestranslucency. On the other hand, an optical energy absorption phenomenonaccording to the electron transition in a material is one of the factorsthat provide translucency. Materials having no cause of the absorptionphenomenon within a desired wavelength area can be the object of makingceramics translucent. It should be noted that the translucent ceramicscan be made by any techniques in the art, and a description thereof isomitted in the present specification.

Since a high temperature strength of the translucent ceramics is large,and the porosity of a sintered material is almost zero, the translucentceramics has features such that a flat and smooth surface is obtainedand gas is not discharged. It should be noted that the translucentceramics suitable for the plate 121 used in the present embodiment hasthe following further characteristics. First, the wavelength dependencyof transmission rate is equal to or greater than that of quartz. Forexample, quartz passes 80% to 90% of light having a wavelength of 0.3 μmto 2.5 μm. Second, the maximum bending stress (σ_(MAX)=68 MPa) exceedsthat of quartz. Third, the heat conductivity is superior to the heatconductivity (1.4 to 1.9 W/mK) of quartz. Fourth, easy to manufacture.

The plate 121 is the translucent ceramics made from Al₂O₃ as mentionedabove, and shows 80% or more of a transmission rate in the wave-lengthrange from 3.5 to 6.0 micrometers on the plate 121 having a thickness of5 mm. Moreover, the maximum bending stress (σ_(MAX)) of Al₂O₃ is 500MPa, which is far greater than that of quartz. Therefore, the plate 121does not need to be formed in a domal shape which curves in a directionto be separated from the process chamber 110 as in the conventionalapparatus, and can have a flat-surface configuration. Although thequartz window formed in a domal shape has a problem of deteriorating adirectivity of a lamp since it increases a distance between an object tobe processed and the lamp, the present embodiment solves such a problem.

In a disk plate of equally distributed load (p), The maximum bendingstress (σ_(MAX)) generated in a disk plate having a radius (a) and athickness (t) can be obtained by the following equation (2) on theassumption that the circumference of periphery of the disk plate isfixed and a load (p) is equally distributed on the plate.σ_(MAX)=3pa ²/4t ²  (2)

In a disk plate of which circumference is fixed and which receives anequally distributed load, if a radius is the same, the maximum bendingstress is in inverse proportion to the 2nd power of the thickness of theplate. Therefore, the thickness of the plate 121 according to thepresent embodiment which has the maximum bending stress 7.4 times thatof quartz can be set about 1/2.7 of a quartz plate. Consequently, theplate 121 of the present embodiment can obtain the same strength byabout one third of the thickness of a conventional quartz plate. Forthis reason, the thickness of the window 120 according to the presentembodiment can be thinner than the conventional quartz window.

The thickness of the plate 121 of the present embodiment may be 5 mm to10 mm, for example, about 5 mm, which thickness is smaller than thethickness of the conventional quartz window which is 30 mm to 40 mm.Consequently, the window 120 of the present embodiment has a smalleramount of absorption of the light from the lamp 130 (described later)than the conventional quartz window. Therefore, since irradiationefficiency to the object to be processed W from the lamp 130 can behigher than the conventional one, a high-speed temperature rise can beattained with a low power-consumption. That is, although there is aproblem in that a lamp light is absorbed by the conventional quartzwindow and the irradiation efficiency to the object W to be processed isreduced, the present embodiment solves such a problem. Moreover, sincethe temperature difference (namely, thermal-stress difference) betweenfront and back surfaces of the plate 121 is lower than that of theconventional quartz window, the window 120 is hardly destroyed. That is,although there is a problem in that a temperature difference arisesbetween a surface of the conventional quartz window which faces a lampand an opposite surface and the quartz window is easily destroyed due tothe thermal-stress difference between the front and back surfaces duringa rapid temperature rise as in a rapid thermal process (RTP), thepresent embodiment solves such a problem.

Furthermore, since the temperature rise of the window 120 is lower thanthe conventional quartz window, in a film deposition process, adeposition film and a reaction byproduct can be prevented from adheringonto the surface of the window 120. Therefore, a good temperaturereproducibility is maintained and the frequency of cleaning of theprocess chamber 110 can be decreased. That is, although there is aproblem that the temperature of the conventional quartz window rises andthe frequency of cleaning of the process chamber is increased whichresults in a deposition film and a reaction byproduct adhering onto thesurface especially during a film deposition process and being unable tomaintain a good temperature reproducibility, the present embodimentsolves such a problem.

Moreover, the heat conductivity of the plate 121 is 34 W/mK, and islarger than 1.4 to 1.9 W/mK which is the heat conductivity of theconventional quartz window. As compared to a quartz plate, the heatconductivity of the plate 121 is 18 to 24 times higher. Consequently,the window 120 of the present embodiment has a temperature differencesmaller than that of the quartz window. Therefore, the energy from thelamp 130 reaches uniformly to the object W to be processed, whichenables uniform heating of the object W to be processed. Therefore, itis possible to carry out uniform heating of the object W to be processedso as to provide a higher quality object W than conventional.

Furthermore, the plate 121 formed of the translucent ceramics is easy toprocess as compared with a quartz plate, thereby the plate 121 is easyto manufacture. It is also possible to arrange a cooling pipe within theplate 121 as mentioned later.

In the present embodiment, although the plate 121 is formed of Al₂O₃, asmentioned above, the present invention is not limited to such amaterial. The plate 121 can be made of any materials is the material canprovide the above-mentioned action and effect. The translucent ceramicsapplicable to the present embodiment may be AlN, Sc₂O₃, MgO,Ca₅(PO₄)₃OH, Si₃N₄, PLZT-8/65/35, Y₂O₃, ZrO₂, ThO₂-5 mol % Y₂O₃, orY₂O₃-10 mol % ThO₂.

A description will now be given, with reference to FIGS. 3 and 4, of awindow 120A as a variation of the window 120 of the present embodiment.FIG. 3 is a bottom plan view of the window 120A which is the variationof the window 120 shown in FIG. 2. FIG. 4 is an enlarged cross-sectionalview of a part of the window 120A shown FIG. 3. The window 120A has areinforcement member 124 having a rectangular cross section under theplate 121 shown in FIG. 3, the reinforcement member 124 made of aluminumor stainless steel (SUS). In FIG. 3, a plurality of reinforcementmembers 124 are linearly arranged. It should be noted that the lamps 130are preferably arranged linearly when using the window 120A, and thereinforcement members 124 are preferably arranged so as to avoidextending directly under the lamps 130 (that is, the lamp light of thelamps 130 is not interrupted by the reinforcement member). However, thereinforcement member 124 may have configurations such as a bent form.The reinforcement member 124 may be bent so as to avoid extendingdirectly under the lamps 130 when the lamps 130 are arranged alongconcentric circles as in the heating unit 14 of the present invention.Since the reinforcement member 124 has a good heat conductivity and ismade of the same material with the process chamber, the reinforcementmember 124 cannot become a pollutant source to the object W to beprocessed. The thickness of the plate 121 of the window 120A can be 5 mmto 10 mm, preferably equal to or less than 5 mm, more preferably equalto or less than 3 mm, which provides the above-mentioned advantages morenotably. In the present embodiment, the cross-sectional dimensions ofthe reinforcement 124 includes a height of about 18 mm and a width ofabout 12 mm in FIG. 4, and a diameter of a cooling pipe is about 6 mm,but the present invention is not limited to such dimensions. Asindicated by arrows shown in FIG. 4, the a light from the lamp 130 isintroduced into the object W to be processed, which is arranged underthe window 120A, by being reflected by side surfaces of thereinforcement members 124.

The reinforcement member 124 has a cooling pipe (cold-water pipe) 125therein so as to further increases the strength of the window 120A. Thecooling pipe 125 of the present embodiment has a function that coolsboth the reinforcement 124 and the plate 121. A cooling pipe 125 cools aplate 121 and has the effect of preventing the thermal deformation dueto a lamp light. Moreover, if the reinforcement member 124 is made ofaluminum, a suitable temperature control is required since aluminum maydeform or melt at a temperature from 200° C. to 700° C. The temperaturecontrol by the cooling pipe 125 may be the same as that of the coolingpipe 116, and any approaches known in the art is applicable.

Next, a description will be given, with reference to FIG. 5, of a window120B as another variation of the window 120 of the present embodiment.FIG. 5 is an enlarged cross-sectional view of a part of the window 120Bwhich is another variation of the window 120 shown in FIG. 2. The window120B comprises the plate 121 and the cooling pipe 125. The plate 121comprises two thin plates 126 and 127 formed of translucent ceramics,and the cooling pipe 125 is arranged between the plates 126 and 127.

The plates 126 and 127 are arranged in line symmetry with respect to thelamination surface 128 indicated by a dotted line in the figure alongwhich the plates 126 and 127 contact with each other. A groove thatreceives the cooling pipe 125 is formed in each of the plates 126 and127, and the plates 126 and 127 are combined by fitting the cooling pipe125 into the grooves. It should be noted that the grooves are arrangedbetween the lamps 130 and to avoid extending directly under the lamps.This structure is enabled since the translucent ceramics has anadvantage in that a local processing can be easily applied to thetranslucent ceramics as compared with quartz. Moreover, the thickness ofthe plate 121, when the plates 126 and 127 are combined, is preferablythe same as the thickness of the plate 121 of the window 120.

The cooling pipe 125 has a circular or elliptic cross section, and isarranged between the plates 126 and 127. Since the cooling pipe 125 isarranged between the plates 126 and 127, there is an advantage in thatthe cooling efficiency for the plate 121 is improved as compared to thewindow 120A. It should be noted that the cooling pipe 125 has the sameeffect as the above-mentioned window 120A, and a detailed descriptionthereof will be omitted.

A description will now be given, with reference to FIGS. 6 through 11,of the heating unit 140 of the present embodiment. FIG. 6 is anillustrative bottom plan view of the heating unit 140 shown in FIG. 2.FIG. 7 is an enlarged cross-sectional view showing a part of the heatingunit 140 shown in FIG. 6. FIG. 8 is a view corresponding to FIG. 7 whenthe lamps 130 are removed from the heating unit 140 shown in FIG. 6.FIG. 9 is an illustrative cross-sectional view of a lamp 130 a shown inFIG. 7. FIG. 10 is an illustrative cross-sectional view of a lamp 130 bshown in FIG. 7. FIG. 11 is an illustrative bottom plan view of the lamp130 shown in FIG. 7. It should be noted that, in FIG. 6 through FIG. 11,the heating unit 140 and the lamps 130 are somewhat exaggerated so as toemphasize the feature of the present invention. The heating unit 140 hastwo kinds of lamps 130 a and 130 b and a lamp support part 142 as a lamphouse, and functions as a heating system which applies a predeterminedheat treatment to the object W to be processed. Here, the lamp 130generically represents the lamp 130 a and the lamp 130 b. In the presentembodiment, the heating unit 140 is separated from the object W to beprocessed so that a distance between the irradiation surface of the lamp130 and the object W to be processed is set to about 40 mm.

Although the lamp 130 is a single-end type in the present embodiment,other energy source such as an electric wire heater may be used. Here,the single-end type refers to a kind of lamp which has a singleelectrode part 132 as shown in FIG. 7. Although the lamp 130 has thefunction to heat the object W to be processed and is a halogen lamp inthe present embodiment, a lamp applicable to the heating unit 140 is notlimited to a halogen lamp. Moreover, although an output of the lamp 130is determined by the lamp driver 310, the lamp driver 310 is controlledby the control part 300 as described later and supplies an electricpower to the lamp 130. It should be noted that, in the presentembodiment, the electric power supplied to the lamp 130 is controlled bythe control part 300 so that the power density of the lamp 130 b islarger than the power density of the lamp 130 a. Specifically, the lamp130 b has a power density two to three times that of the lamp 130 a.

As shown in FIG. 6, in the present embodiment, the lamps 130 arearranged along almost concentrically so as to correspond to the almostcircular object W to be processed (in FIG. 6, the number of lamps 130shown is reduced). Moreover, the lamps 130 a having a larger diameterare arranged in a position corresponding to the vicinity of the centerof the object W to be processed, and the lamps 130 b having a smallerdiameter are arranged in a position corresponding to the vicinity of thesupport ring 150 and the end of the object W to be processed. It shouldbe noted that the lamps 130 are later described with reference to a lampsupport part 142.

Typically, the lamp 130 has a single electrode part 132, a middle part134 and a light-emitting part 136 connected to the electrode part 132via the middle part 134. The light-emitting part 136 comprises a coilpart 138 and a reflector 139. The coil part 138 is provided to afilament 137 connected to the electrode part 132 via the middle part134. In the present embodiment, a thread (external thread) 131 is formedon a side of the lamp support part 142, which faces a groove 143described later. The thread 131 is a triangular screw thread in thepresent embodiment, and a generally triangle-shaped ridge is formed. Itshould be noted that the thread 131 is not limited to theabove-mentioned configuration, and may be a square thread or atrapezoidal thread. However, the lamp 130 does not always require thethread 131, and the lamp 130 having no thread may be used.

In the present embodiment, the height of the electrode part 132 of thelamp 130 a is about 25 mm, the height of the middle part 134 is about 45mm and the height of the light-emitting part 136 is about 25 mm.Moreover, the diameter of the middle part 134 is about 10 mm and thelight-emitting part 136 of the diameter of the middle part 134 is about40 mm. On the other hand, the height of the electrode part 132 of thelamp 130 b is about 25 mm, the height of the middle part 124 is about 55mm, and the height of the light-emitting part is about 10 mm. Moreover,the diameter of the middle part 134 is about 10 mm, and the diameter ofthe light-emitting part is about 20 mm.

The electrode part 132 has a pair of electrodes 133 and is connectedwith the lamp driver 310 electrically through the lamp support part 142.The electrodes 133 are electrically connected to the filament 137. Theelectric power supplied to the electrode part 132 is determined by thelamp driver 310, and the lamp driver 310 is controlled by the controlpart 300. A seal part 143 c mentioned later connects between theelectrode part 132 and the lamp driver 310.

The middle part 134 is formed airtight with the light-emitting part 136.Nitrogen, argon or halogen gas is enclosed within the interior of themiddle part 134. The middle part 134 is a cylinder, which is locatedbetween the electrode part 132 and the light-emitting part 136 and has apredetermined length so as to separate the electrode part 132 and thelight-emitting part 136 from each other. The middle part 134 has anadvantage in that the length thereof is preferable for the temperaturecontrol of the lamp 130 described later. It should be noted that sincethe filament 137 positioned inside the middle part 134 emits a light, itis natural that the filament is a part of the light-emitting part 136.However, in this specification, since the electrode part 132 and thelight-emitting part 136 (the part which emits light most strongly) areseparated by a predetermined distance, this area is defined merelydefined as the middle part 134. In the present embodiment, the middlepart 134 is formed of ceramics. However, the middle part 134 may beformed of a metal other than ceramics, such as aluminum or SUS(stainless steel).

The light-emitting part 136 has the cylindrical shape having a diameterlarger than the middle part 134 in the present embodiment. Thelight-emitting part 136 comprises a side surface 136 a inscribed with agroove 143 and a projecting surface 136 b, which faces the object W tobe processed and from which a lamp light is projected. Thelight-emitting part 136 has the coil 138 of the filament 137 and thereflector 139 inside thereof. In the present embodiment, the sidesurface 136 a of the light-emitting part 136 is fabricated integrallywith the middle part 134 by the same material as the middle part 134. Onthe other hand, the projecting surface 136 b of the light-emitting part136 is formed of a material such as quartz or translucent ceramics,which transmits the lamp light.

The thread 131, which is explained later, is formed on the side surface139 of the lamp 130 although the side face 139 is fundamentally formedin a hemisphere, a half-ellipse sphere or a cone. Then, as shown inFIGS. 7, 9 and 10, according to the present embodiment, in order to formthe thread 131, the configuration of the side surface 136 b differs fromthe hemisphere and the circular cone configuration, and is should beunderstood that the light-emitting part 136 is illustrated as beingdeformed. Moreover, the shape of the reflector 137 mentioned later has ashape the same as the side surface 136 a and has a hemisphere shapebecause the side surface 136 a are illustrated as being deformed.

The filament 137 is made of tungsten (W). As shown in FIGS. 8 through10, the filament 137 is connected to the electrodes 133 and constitutesthe coil 138 which can be an illuminant in the light-emitting part 136.The axial center of the coil 138 is formed so as to be parallel to theobject W to be processed. The light emitted from the filament 137 isirradiated in a normal direction of the coil 138 (a directionperpendicular to the axial direction of the coil 138). Therefore, atleast a light from the side of the coil 138, which faces the object W tobe processed, is directly irradiated onto the object W to be processed(without associated with the reflector 139). The reflective loss of sucha light due to association with the reflector 139 is zero, and the lightis irradiated onto the object W to be processed while maintaining a highenergy. On the other hand, lights other than the above-mentioned lightare efficiently reflected by the reflector 139 mentioned later, and areirradiated onto the object W to be processed.

The reflector 139 covers the coil 138 and has a convex hemisphereconfiguration in a direction away from the object W to be processed. Thereflector 139 is a reflective part which reflects a light toward theobject W to be processed, and, more specifically, is formed in the sameshape as the side surface 136 a of the light-emitting part 136. However,in FIGS. 7, 9 and 10, since the thread 131 is formed on thelight-emitting part 136, the configuration of the light-emitting part136 is changed as mentioned above. Moreover, the configuration of thereflector 139 is not limited to a hemisphere configuration, will noteliminate other configurations if the configuration of the reflector 139is substantially the same as that of the side surface of thelight-emitting part 136. For example, the reflectors 139 may be in theform of a half-ellipse globular form or a cone form. Moreover, thereflector 139 has a penetration holes (not shown in the figures) whichallow the filament 137 passing therethrough so as to be connected to theelectrodes 133 and cover the coil 138. However, the penetration holesare preferably formed so as not to affect the reflective function of thereflector 139. Furthermore, the surface of the reflector 139 coveringthe coil 138 is provided with a coating so as to efficiently reflect alight including a visible light and an infrared light. It is possible touse gold (Au), gold (Au) and rhodium (Rh), or gold (Au) and nickel (Ni)as a material for the coating.

The reflector 139 has the function which improves the directivity of thelamp 130 while reflecting a light emitted by the coil 138 toward theobject W to be processed. The reflector 139 efficiently reflects a lightemitted by the coil 138 toward the object W to be processed, preferablyby only one reflection, and converge the light in a directionsubstantially perpendicular to the object W to be processed.

A description will be given, with reference to FIGS. 12 and 13, of anoptical path of the lamp 130. FIG. 12 is an illustrative side view ofthe lamp 130 indicating optical path of a light L emitted from thefilament 137. The light L generically represents lights L1, L2 and L3emitted from the filament 137 of the lamp 130 shown in FIG. 7. FIG. 13is another illustrative side view of the lamp 130 indicating opticalpath of a light L emitted from the filament 137. The light L1 emittedfrom the top surface (the side which faces the object W to be processed)of the coil 138 travels in a direction away from the reflector 139. Asmentioned above, since the reflector 139 reflects the light so as totravel toward the object W to be processed, the light L1 is reflected bythe reflector once and travels toward the object W to be processed. Inaddition, a part of the light L1 reaches the filament 137, which is notirradiated onto the object W to be processed. However, since the energyof such a part of the light L1 contributes heating and luminescence ofthe coil 138, there is no energy loss. Moreover, the light L2 emittedfrom the side of the coil 138 is incident on the reflector 139, and alarge part of the light L2 is irradiated onto the object W to beprocessed, and the reset returns to the filament 137, which contributesthe luminescence of the coil 138 as mentioned above. Finally, the lightL3 emitted from the undersurface side (the side which faces the object Wto be processed) of the coil 138 is directly irradiated onto the objectW to be processed without reflection of the reflector 139.

As explained above, the lamp 130 of the present embodiment projects alight in a direction perpendicular to the object W by positioning thecoil 138 of the filament 137 parallel to the object W to be processed.The light of is directly irradiated onto the object W to be processed,and other lights travels toward the reflector 139. Moreover, asmentioned above, the reflector 139 is formed so that a light isreflected toward the object W to be processed. Therefore, the lightemitted from the lamp 130 is irradiated onto the processed with only onereflection by the reflector 139. Moreover, the light emitted from thelamp 130 is converged within a range of an opening of the reflector 139in a tangential direction. Namely, the lamp 130 according to the presentembodiment is reflected less number of times than the conventional lampshown in FIG. 1. For this reason, the light is transmitted to the objectW to be processed with little energy loss, and is excellent also indirectivity. Although there is a problem in that the energy of the lamplight is reduced by the reflective loss associated with multiplereflection by the reflector, the present embodiment solves such aproblem. Therefore, since the lamp 130 can improve the irradiationefficiency to the object W to be processed, a high-speed temperaturerise can be attained at a low power consumption. It should be noted thatthe curvature and opening of the reflector 139 may vary in accordancewith a desired directivity to be achieved.

Moreover, since the thread 131 applicable to the groove 143 of the lampsupport part 142 is formed on the side surface of the lamp 130, themiddle part 134 and the light-emitting part 136 of the lamp 130 areformed of the above-mentioned material in consideration of the strengthand machinability. However, the lamp 130 of the present embodiment isnot limited to such a material, and an entire middle part 134 andlight-emitting part 136 may be formed of quartz or translucent ceramics.However, in such as case, it is necessary to provide a cover material tothe lamp 130 and to acquire a strength and machinability in the coverwith respect to the lamp support part 142. Furthermore, it is preferableto select the cover material from materials having a high heatconductivity so as not to prevent cooling of the lamp 130. On the otherhand, in the lamp 130, the side surface 136 b of the light-emitting part136 may be formed in a hemisphere or a cone form as mentioned above.Furthermore, the light-emitting part 136 and the middle part 134 may beformed in cylindrical shapes having the same diameter. However, theconfiguration of the lamp 130 mentioned above has many advantages asmentioned above.

A description will now be given, with reference to FIG. 14, of a lamp130A as a variation of the lamp 130 of the present embodiment. FIG. 14is an illustrative bottom plan view of the lamp 130A which is avariation of the lamp 130 shown in FIG. 7. The lamp 130A has filament137A which constitutes a plurality of coils 138 a through 138 c. Similarto the filament 137 mentioned above, the coils 138 a to 138 c arearranged parallel to the object W to be processed. Accordingly, when thelamp 130A is seen from the object W, light-emitting part 136 of the lamp130A can be regarded as a surface illuminant. That is, the lamp 130A haslarger irradiation energy than the lamp 130. Therefore, since theirradiation efficiency to the object W to be processed can be higherthan the lamp 130, a high-speed temperature rise can be attained.Moreover, the thus-structured lamp 130A has little reflective loss ofthe reflector 139 as described with the lamp 130, and has a directivity.

It should be noted that, in the lamp 130A, the number of coils 138 athrough 138 c, which constitute filament 137A, can be changed inaccordance with a desired irradiation energy. Moreover, the arrangementand configuration of the filament 137A are sufficient for the lamp 130Ato be regard as a surface illuminant with respect to the object W to beprocessed. That is, the arrangement of the filament 137 as shown inFIGS. 15 through 18 may be used. Here, FIG. 15 through FIG. 17 areillustrative plan views showing filaments 137B trough 137D which arevariations of the filament 137A of the lamp 130A shown in FIG. 14. FIG.18 is an illustrative side view of the filament 130D shown in FIG. 17.FIG. 15 shows the filament 137B arranged so that a plurality of coils138 d through 139 g cross each other. FIG. 16 shows the filament 137Cwhich has a coil 138 h formed with a large width. FIGS. 17 and 18 showthe filament 137D in which a coil 138 i forms a spiral. Even in theconfiguration mentioned above, it can consider that the lamp 130A is asurface illuminant, and it is possible to raise the irradiation energyof the lamp.

Referring to FIGS. 6 through 8 and FIG. 19, the lamp support part 142which functions as a lamp house with has a substantially rectangularparallelepiped shape, and has the grooves 143 which contain therespective lamps 130 and isolation wall 148. FIG. 19 is an enlargedcross-sectional view of a part of the lamp support part 142 shown inFIG. 7 when the lamp 130 is not expanded. The groove 143 serves as alamp accommodation part which accommodates the lamp, and comprises agroove 143 a which accommodates the lamp 130 a and a groove 143 b whichaccommodates the lamp 130 b. It should be noted that the groove 143generically represents the grooves 143 a and 143 b. The configuration ofthe groove 143 will be described later, a description will now be givenof an arrangement of the grooves 143.

As shown in FIG. 6, the groove 143 a is formed along concentric circlesarranged in an area from the center of the lamp support part 142 (aposition corresponding to the center of the object W to be processed) tothe vicinity of the support ring 150 in a radial direction. Morespecifically, a plurality of grooves 143 a are formed along theconcentric circles of which radius is increased by a first distance fromthe center so that the center of each of the grooves 143 a is positionedon the corresponding concentric circles. The first distance is set toabout 0.5 to 1.5 times a half-value width of a radiation distribution.The half-value width corresponds to a width of the radiationdistribution when an intensity of the light of the lamp 130 a is onehalf of a peak value. In the present embodiment, the lamp 130 a showsthe half-value width of about 40 mm in a direction of radiation of thelamp light at a point about 40 mm from the projecting surface 136 b. Thedistance of 40 mm corresponds to the distance between the lamp 130 andthe object W to be processed. It should be noted that the half-valuewidth differs from lamp to lamp, and the present invention is notlimited to this value. Moreover, in the present embodiment, since thecooling pipe 149 mentioned later is provided in the light-emitting-part136, the first distance is set to 50 mm (1.25 times the half-valuewidth) which is a lager value than the diameter of the light-emittingpart 136 of the lamp 130 a. It should be noted that the concentriccircles may be extended to the location at which the concentric circlesdo not overlap with a groove 143 b mentioned later. Moreover, it ispreferable that an interval between the grooves 143 a arranged along oneof the concentric circles be set equal to the first distance.

On the other hand, the grooves 143 b are formed along a plurality ofconcentric circles within and in the vicinity of an area where thesupport ring 150 overlaps with the object W to be processed. Morespecifically, the grooves 143 b are arranged along first, second andthird circles C1, C2 and C3. The first circle is located within the areawhere the support ring 150 overlaps with the object W to be processed.The second circle C2 has a radius larger than the radius of the firstcircle by a second distance. The third circle C3 has a radius smallerthan the radius of the first circle by the second distance. It should benoted that the second distance is set to about 0.5 to 1.5 times thehalf-value width of a radiation distribution of the lamp 130 b. The lamp130 b shows the half-value width of about 20 mm in a direction ofradiation of the lamp light at a point about 40 mm from the projectingsurface 136 b. In the present embodiment, the distance of 40 mmcorresponds to the distance between the lamp 130 and the object W to beprocessed. It should be noted that the half-value width differs fromlamp to lamp, and the present invention is not limited to this value.Moreover, similar to the grooves 143 a, since the cooling pipe 149mentioned later is provided in the light-emitting-part 136, the seconddistance is set to 25 mm (1.25 times the half-value width). Moreover, itis preferable that an interval of the grooves 143 b along one of thecircles be set equal to the second distance.

In the present embodiment, although the grooves 143 b are formed alongthe three circles C1, C2 and C3, the number of circles is not limited tothree and may be changed to an appropriate value. As mentioned above,the grooves 143 b are formed so that the lamps 130 b can irradiate thearea where the support ring 150 and the object W to be processed overlapwith each other. For example, when the object W to be processed islarger than the circle C2, additional grooves 143 b may be arrangedalong a circle having a diameter larger than the diameter of the circleC2 by a length equal to the second distance. Similarly, when the supportring 150 is smaller than the circle C3, additional grooves 143 b may bearranged along a circle having a diameter smaller than the diameter ofthe circle C3 by a length equal to the second distance.

In the structure mentioned above, the lamp support part 142 enablesarrangement of the lamps 130 a at the positions in the vicinity of theobject W to be processed and the lamps 130 b in the part where a supportring 150 overlaps with the object W to be processed and in the vicinityof the part concerned. FIG. 22 is an illustration of lights irradiatedby the lamps 130 a of the heating unit 140 shown in FIG. 2 onto theobject W to be processed. FIG. 23 is an illustration of lightsirradiated by the lamps 130 b of the heating unit 140 shown in FIG. 2onto the object W to be processed. If the lamp 130 irradiates in thestate shown in FIGS. 22 and 23, a greater irradiation area can beobtained by the lamps 130 a in the center of the object W to beprocessed. On the other hand, a smaller irradiation area can be obtainedby the lamps 130 b in the vicinity of the outer end of the object W tobe processed. It should be noted that FIGS. 22 and 23 illustrate thelamp lights as an example, and the number of lamps 130 does not matchthe present embodiment.

In the present embodiment, it becomes possible to irradiate efficientlythe small area where the support ring 150 and the end of the object W tobe processed overlap with each other by arranging the small-diameterlamps 130 b around the lamps 130 a. Moreover, as mentioned above, theelectric power supplied to the lamp 130 b is larger than the electricpower supplied to the lamp 130 a. That is, an energy irradiated by thelamps 130 b per unit area is greater than that of the lamps 130 a.According to the arrangement of lamps in the conventional heat treatmentapparatus, it is impossible to control the lamp irradiation areaseparately between the center area and the end area of the object W tobe processed since only one kind of lamp is used.

The specific heat differs from the support ring 150 to the object W tobe processed. Specifically, the specific heat of the support ring 150 issmaller than the specific heat of the object W to be processed.Therefore, there is a problem in that the a temperature siring rate ofthe area where the support ring 150 overlaps with the object W to beprocessed and the area in the vicinity of the area concerned is smallerthat other areas of the object W to be processed. However, in thepresent embodiment, since the small area in the periphery of the objectW to be processed is irradiated by the small-diameter lamps 130 b, theobject W to be processed can be efficiently heated. Furthermore, thecenter area and the peripheral area of the object W to be processed areprevented from being heated unevenly, which results in a high-qualityheat treatment process. Moreover, using the large-diameter lamps 130 ain the vicinity of the center of the object W provides a largeirradiation area by one of the lamps 130 a. Therefore, the number of thelamps 130 in the vicinity of the center can be smaller than conventionalone, which allows a reduction in the power consumption. In the presentembodiment, the above-mentioned problem is solved by using the lamps 130a and 130 b having different diameters and varying an electric powersupplied to the lamps 130 a and 130 b.

As shown in FIG. 24, the lamps 130 b may be inclined so that the lightsirradiated by the adjacent lamps 130 b located in the outermost area ina radial direction overlap with each other on the object W to beprocessed. FIG. 24 is an illustrative cross-sectional view showing avariation of the arrangement of the lamps 130 shown in FIG. 7. Thisstructure has an effect to increase the irradiation density of the lampsin the periphery of the object to be processed, and is further effectivein preventing uneven heating between the center area and the peripheralarea.

It should be noted that the arrangement of the grooves 143 is notlimited to the concentric arrangement, and other arrangements such as,for example, a linear arrangement or a spiral arrangement may be used ifsuch an arrangement satisfies the above-mentioned conditions. Moreover,in the present embodiment, since the opening configuration of thereflector 139 of the lamp 130 is circular, the irradiation configurationof the lamp light is circular. However, the lamp 130 does not havelimitation in the irradiation configuration in view of the concept thatthe lamps having a large irradiation area located in the center ofobject W to be processed and the lamps having a small irradiation areaare located in the peripheral area of the object W to be processed. Forexample, the configuration of the lamp 130 and/or the reflector 139 maybe changed so that the irradiation area becomes a triangle. In addition,the configuration of the lamp light may not be limited to a triangle butmay be other polygons such as a square or hexagon. Moreover, anyirradiation approaches, which can provide similar effect, may be used.

A description will now be given of the configuration of the groove 143.The groove 143 has the same configuration as the lamp 130, and comprisesa part 143 c which accommodates the electrode part 132 of the lamp 130,a part 143 d which accommodates the middle part 134 and a part 143 ewhich accommodates the light-emitting part 136. The part 143 c connectsthe electrode part 132 to a lamp driver 310 shown in FIG. 2, and servesas a seal part which gives a seal between the electrode part 132 and thelamp driver 310. The groove 143 has a thread (female screw) 147 formedon a part inscribing with the lamp 130. In the present embodiment, thethread 147 is a triangular screw thread which matches the thread formedon the lamp 130. It should be noted that the shape of the thread profileis not limited to the triangular profile, and if the thread 131 of thelamp 130 is a square screw or a trapezoidal screw thread, the thread 147of the groove 143 is also formed to correspond to the thread 131 of thelamp 130. In addition, the groove 143 is formed so that the thread 147optimally fits to the thread of the lamp 130 when the lamp 130 expandsthermally. That is, when the lamp 130 is not thermally expanded, theouter and inner diameter and the pitch of the thread 147 formed in thegroove 143 are slightly larger than that of the thread 131 formed on thelamp 130. However, the difference between the dimensions of the threadsis such that insertion of the lamp 130 and engagement with the groove134 are not prevented.

In the above-mentioned structure, the groove 143 and the lamp 130 have arelationship of a nut and a bolt. The lamp 130 can be attached to thegroove 143 by inserting the lamp support part 142 into the groove 143while rotating so as to engage the threads with each other. As shown inFIG. 19, when the lamp 130 is in a normal state where the lamp 130 doesnot expand thermally, the threads of the lamp 130 and the groove 143engages with each other at surfaces in the direction of gravity. Thatis, a contact area is maintained between the lamp 130 and the groove143. Although such a contact area is necessary to retain the lamp 130,there is a problem as mentioned below. The groove of the lamp supportpart of the conventional lamp has the same cylindrical shape with thelamp to be inserted into the groove. The groove is formed so that, whenthe lamp is thermally expanded and becomes a maximum size, the lampcompletely fits in the groove. That is, in the conventional structure,when the lamp is not completely expanded, the cooling effect of thecooling pipe, which is provided in the lamp support part to cool thelamp, deteriorates since the contact area between the lamp and thegroove is small. The present embodiment eliminates such a problem.Moreover, since the ridge of the thread 147 of the groove 143 isslightly larger than the ridge of the thread 131 of the lamp 130, thereis formed a small space between the groove 143 and the lamp 130. Thegroove 143 and the lamp 130 are configured to fit with each other whenthe lamp 130 is heated and expanded thermally so that the small spacepermits the thermal expansion of the lamp 130 within the groove 143.

Furthermore, the configuration of the lamp 130 and the configuration ofthe groove 143 have the following advantages. If an output of a part ofthe lamps is increased, the part of the lamps may degrade faster.Moreover, the reflector also degrades faster if a larger power issupplied to the lamp. Therefore, a high-output lamp has a shorterservice life than a low-output lamp. Similarly, a reflector for thehigh-output lamp has a shorter service life than a reflector for thelow-output lamp.

Consequently, in order to exchange the lamp and reflector of whichservice life has expired located in the peripheral area of the lampsupport part, it is required to exchange the entire lamp support partincluding the lamps and reflectors which area still usable, which is notan economical way. However, in the present embodiment, the groove 143and the lamp 130 of the lamp support part 142 have a relationship of anut and a bolt as mentioned above, and, thereby, the lamps 130 can beremoved on an individual lamp basis.

Therefore, the usable lamps 130 can be continuously used by replacingonly degraded lamps 130. Thus, the present embodiment solves theabove-mentioned problem by constituting the lamps being easilyreplaceable on an individual lamp basis. Moreover, the presentembodiment eliminates a replacement work of the entire lamp supportpart, which is complex and inconvenient, and, thus, there is a furtheradvantage that the maintenance efficiency is improved.

A description will be given, with reference to FIGS. 20 and 21, of agroove 143A which is a variation of the groove 143 of the lamp supportpart 142. FIG. 20 is an illustrative cross-sectional view of the lampsupport part 142 of the heating unit 140 shown in FIG. 6. FIG. 21 is anillustrative bottom plan view of the lamp support part 142 of theheating unit shown in FIG. 6. It should be noted that FIG. 21 shows astate where the lamp 130 is removed. The lamp 130 applicable to thegroove 143A does not need the thread 131, and, thus, a lamp 130B havingno thread is used.

The groove 143A has a slightly larger configuration than the lamp 130Bso as to accommodate the lamp 130B therein. Moreover, the groove 143Ahas a plurality of thin plates 144 inscribed with an inner surface ofthe groove 134A. The thin plates 144 serves as leaf springs so as tohold the lamp 130B.

Each of the thin plates 144 is formed in a rectangle shape in thepresent embodiment, and is fabricated by an aluminum plate or astainless steel plate. Each end of the thin plate 144 in a longitudinaldirection is bent in the form of L-shape. Furthermore, each of the thinplates 144 has a curvature equal to the curvature of the side surface ofthe lamp 130B. As shown in FIGS. 20 and 21, the opposite ends of each ofthe thin plates 144 contact the inner surface of the groove 143A, andare joined to the inner surface by means of, for example, welding.

Each of the thin plates 144 forms a space 145 between the inner surfaceof the groove 143A and the thin plate 144. The space 145 is formed dueto the bending process applied to the thin plate 144, and the space 45can be set to a desired size by changing a position of a part to bebent. The space 145 is provided so that thin plate 144 can moveoutwardly in a radial direction of the groove 143A when the lamp 130Bexpands thermally within the groove 143A.

In the present embodiment, eight thin plates 144 are arranged along theinner surface of the groove 143A while maintaining a predetermined gap146 between the adjacent thin plates 144. In this structure, the thinstrips 144 together form a substantially octagonal cross section withinthe groove 143A. In addition, the gap 146 is set so that the adjacentthin plates do not contact with each other when the thin plates 144 ispressed and deforms in a radial direction of the groove 143A. Similarly,three thin plates 144 are arranged along the longitudinal direction ofthe groove 143A. That is, in the present embodiment, the groove 143A has24 (=8×3) sheets of the thin plates 144 arranged on the inner surfacethereof. Thus, the lamp 130B just or tightly fits in the groove 143A ina state where the thin plates 144 are provided in the groove 143A.

In above-mentioned structure, the groove 143A holds the lamp 130B by theaction of the thin plates 144. More specifically, the lamp 130B is heldby the groove 143A by being strongly pressed into the space defined bythe thin plate 144. At this time, the thin plates 144 elastically deformdue to the insertion of the lamp 130, and the lamp 130 is tightly fittedin the groove 143A. Therefore, the lamp 130B is held in the groove 143Aby a restoration force and frictional force of the thin plates 144, andalmost the entire side surface of the lamp 130B contacts the thin plates144.

Moreover, even when the lamp 130B expands thermally, the lamp 130B isheld within the groove 143A since the thin plates 144 follow the thermalexpansion of the lamp 130B. Accordingly, the present embodimenteliminates the problem of less contact area between the lamp and innersurface of the groove into which the lamp is inserted, by providing thethin plates in the groove. Moreover, even in the above-mentionedstructure, a partial replacement of the lamps can be carried out. Thatis, the usable lamps 130 can be continuously used by replacing onlydegraded lamps 130. Thus, the present embodiment solves theabove-mentioned problem by constituting the lamps being easilyreplaceable on an individual lamp basis. Moreover, the presentembodiment eliminates a replacement work of the entire lamp supportpart, which is complex and inconvenient, and, thus, there is a furtheradvantage that the maintenance efficiency is improved.

It should be noted that the number of thin plates 144 and theirconfiguration are not limited to that described above. For example, thespace formed inside the groove by the thin plates 144 is not limited tothe octagonal cross section, and a polygonal shape other than theoctagonal shape may be used. However, it is preferable that the crosssection can be regarded as a substantially circular shape. Although thepreferable form of the groove 143 holding the lamp 130 has beenexplained, the present invention is not limited to the specificallydisclosed embodiments, and other form may be used if the same action andeffect can be obtained. Moreover, the form of the groove 143 is notlimited to the use of the configuration of the lamp 130, and may beapplied to other lams known in the art.

As shown in FIGS. 7 and 8, the isolation wall 148 is arranged betweenthe adjacent grooves 143 which are arranged along the concentriccircles. In the present embodiment, the thickness of the isolation wall148 between the parts 143 c is about 50 mm, and the thickness of theisolation wall between the parts 143 e is about 10 mm. Moreover, thethickness of the isolation wall between the parts 143 c of groove 143 bis about 15 mm, and the thickness of the isolation wall between theparts 143 e is about 5 mm. The isolation wall 148 is provided with apair of cooling pipes (cooling water pipes) 149 a and 149 b. Hereinaftera cooling pipe 149 generically represents the cooling pipes 149 a and149 b. More specifically, the cooling pipe 149 a is located in the placecorresponding to the electrode part 132 of the lamp 130, and the coolingpipe 149 b is located in the place corresponding to the light-emittingpart 136 of the lamp 130.

The cooling pipe 149 is connected to the temperature-control devicewhich is not shown in the figure. The temperature-control devicecomprises the control part 300, a temperature sensor or thermometer anda heater. A cooling water is supplied to the temperature-control devicefrom a water source such as a water line. Instead of the cooling water,other coolants such as alcohol, gurden, chlorofluorocarbon, etc. may beused. As for the temperature sensor, a well-known sensor such as, forexample, a PTC thermistor, an infrared sensor or a thermocouple may beused. A temperature sensor or thermometer measures a temperature of theinner wall of the electrode part 132 and the light-emitting part 136 ofthe lamp 130. A heater is constituted by a wire heater wound on an outersurface of the cooling pipe 116. By controlling the magnitude of thecurrent, which flows through the wire heater, the temperature of thewater flowing through the cooling pipe 149 can be adjusted.

When the electrodes 133 are made of molybdenum, in order to preventdestruction of the electrodes 133 and seal part 143 c due to oxidizationof molybdenum, the cooling pipe 149 a maintains the temperature of theseal part 143 c at 350° C. or less. Moreover, the cooling pipe 149 bmaintains the temperature of the light-emitting part 136 at 250° C. to900° C. so that the middle part 134 and the light-emitting part 136maintain a halogen cycle. In the halogen cycle, the tungsten whichconstitutes the filament 137 evaporates and reacts with halogen gas, atungsten-halogen compound is generated which floats inside the lamp 130.When the lamp 130 is maintained at 250° C. to 900° C., thetungsten-halogen compound maintains the floating state.

However, when the tungsten-halogen compound is carried to the vicinityof the filament 137 by convection, the tungsten-halogen compound isdecomposed into tungsten and halogen gas due to the high-temperature ofthe filament 137. Then, the tungsten is deposited on the filament 137and the halogen gas repeats the same reaction. It should be noted that,generally, if the temperature exceeds 900° C., devitrification (aphenomenon in which the light-emitting part 136 becomes white) mayoccur. On the other hand, if the temperature is below 250° C.,blackening (phenomenon in which the tungsten-halogen compound adheres tothe wall of the lamp 130, and becomes black) may occur.

In the present embodiment, the cooling pipe 149 a is maintained at atemperature within the range of halogen cycle and which can preventoxidization of molybdenum. Such a temperature preferably ranges from250° C. to 350° C. Additionally, the cooling pipe 149 b is maintained ata temperature within the range of halogen cycle, preferably at atemperature ranging from 800° C. to 900° C. Although the coolingtemperature for the light-emitting part 136 can be in the range of 250°C. to 900° C., when the cooling efficiency is taken into consideration,the cooling temperature is preferably set to an upper limit temperatureof the halogen cycle since cooling can be carried out with a lesselectric power.

The cooling pipe 149 a is at the common temperature for halogen cycleand oxidization prevention of molybdenum, and the light-emitting part136 is maintained by the cooling pipe 149 b within the halogen cycletemperature range. Moreover, a temperature slope arises in the lamp 130due to the separate cooling pipes 149 a and 149 b in accordance with thelength of the middle part 134 of the lamp 130. The temperature slope(250° C. to 950° C.) maintains the entire lamp 130 within the halogencycle temperature range. That is, although there is a possibility thatthe temperature (800° C. or 950° C.) of the light-emitting part 136 mayinfluence the temperature (250° C. to 350° C.) of the seal part 143 c ifthe light-emitting part 136 and the seal part 143 c are close to eachother such a problem is solved by providing the middle part 134 in thelamp 130 according to the present embodiment.

According to the present embodiment, devitrification and blackening ofthe lamp 130 can be suppressed. Moreover, the electrode part 132 and theseal part 143 c are prevented form being damaged due to oxidization ofthe molybdenum of the electrodes 133. Furthermore, the lamp 130 iscooled so as to be at a temperature within the halogen cycle temperaturerange. A conventional cooling system of the lamp 130 merely cools theseal part 143 c, and the cooling in accordance with the halogen cycle isnot carried out. Therefore, the cooling pipe 149 according the presentinvention has an advantage of elongating the service life of the lamp130. It should be noted that the contact area between the groove 143 andthe lamp 130 is larger than that of the conventional structure asmentioned above, and it is possible to acquire a sufficient coolingeffect.

It should be noted that instead of providing the isolation wall 148between parts corresponding to the light-emitting parts 136 of the lamps130, the space provided with the isolation wall 148 may be empty so asto carry out air cooling for the light-emitting parts 136. The seal part143 c shall be cooled by the above-mentioned cooling pipe 149 a. Sincethe light-emitting part 136 is to be cooled at a relatively hightemperature of 800° C. to 900° C., the light-emitting part 136 can becooled by air cooling so as to obtain the same action and effect asmentioned above. The air cooling may be carried out by a known coolingsystem such as a blower, which carries out forced air cooling.Furthermore, another cooling method in which a common cooling pipe isprovided so as to cool both the isolation wall 148 and thelight-emitting part 136 may be used. In such a method, the cooling pipemay be cooled at a temperature of 250° C. to 350° C., which is atemperature common to both the oxidization prevention of molybdenum andthe halogen cycle range. Even with the above-mentioned structure, thesame effect as the above-mentioned cooling pipe 149 can be acquired.

A description will now be given of the radiation thermometer 200. Theradiation thermometer 200 is provided on the opposite side of the lamp130 with respect to the object W to be processed. Although the presentinvention does not exclude a structure in which the radiationthermometer 200 is provided on the same side with the lamp 130, it ispreferable that a light form the lamp 130 is prevented from beingincident on the radiation thermometer 200.

The radiation thermometer 200 is attached to a bottom part 114 of theprocess chamber 110. A surface of the bottom part 114 that faces insidethe process chamber 110 serves as a reflective plate (high-reflectancesurface) by being provided with gold plating. This is for the reasonthat is the surface of the bottom part 114 is a low-reflectance surfacesuch as a black surface, the surface absorbs the heat emitted from theobject W to be processed, which uneconomically requires an increase inthe irradiation output of the lamp 130. The bottom part 114 has acylindrical through hole. The radiation thermometer 200 can be any knowndevice, and a description thereof will be omitted. The radiationthermometer 200 is connected to the control part 300, and the controlpart 300 computes a temperature T of the object W to be processed. Itshould be noted that an arithmetic part (not shown in the figure)provided in the radiation thermometer 200 may carry out the arithmeticoperation of computing the temperature T. The control part 300 canobtain the temperature T of the object W to be processed from theradiation thermometer 200.

The control part 300 comprises a central processing unit (CPU) and amemory. The control part 300 carries out a feedback control of theoutput of the lamp 130 by recognizing the temperature T of the object Wto be processed so as to control the lamp driver 310. In the presentembodiment, the control part 300 continues to maintain the temperatureof the lamp 130 in the halogen cycle temperature range by controllingthe lamp driver 310 when an electric power is supplied to the lamp 130.That is, an electric power is continuously supplied to the lamp driverfrom a time when the driver 310 after a main switch of a cluster tool(not shown in the figure) including the heat treatment apparatus 100 isturned on and until the main switch of the cluster tool is turned off.At this time, an electric power is also continuously supplied to thelamp 130 through the lamp driver 310.

It should be noted that, as mentioned above, the lamp 130 is controlledwithin the halogen cycle temperature range. Therefore, the temperatureof the lamp 130 rises to about 900 degrees C. at the time of heating,and is maintained at 250 degrees C. or more even at the time of cooling.The object W to be processed is heat-treated within this temperaturerange. It should be noted that the temperature control of the lamp 130may be achieved by a feedback control in which an electric power to besupplied is varied using the temperature sensor or thermometer of thetemperature-control system connected to the cooling pipe 149 b.Alternatively, a function representing a relationship between thetemperature of the lamp 130 and the function of the electric power to besupplied is calculated so as to supply an electric power to the lamp 130based on a temperature expected according to the function.

In the conventional heat treatment apparatus, an electric power is notsupplied to the lamp driver 310 and the lamp 130 except for a heattreatment operation. That is, a control is made to drive the lamp driver310 so as to supply a desired electric power to the lamp 130 only at thetime of heating. However, the filament 137 of the lamp 130 has a verysmall resistance at a room temperature, and will be almost in ashort-circuit state at the moment of supply of a voltage. In such astate, even in a case where there is an external resistance, a currentof seven to ten times the rated current value flows. When there is noexternal circuit resistance, a rush current of thirteen to seventeentimes the rated current flows, which is an occurrence of a rush currentphenomenon. In the heat treatment apparatus which rapidly turns lamps onand off in response to up and down of a temperature of the object W tobe processed, the rush current phenomenon occurring at every powersupply time is a cause of degradation of the lamps and the lamp driver.

In the present embodiment, the power supply to the lamp 130 is anecessary minimum thing related to a start of the cluster toolcontaining the heat treatment apparatus 100, and the lamp 130 is notturned on and off in response to up and down of the temperature of theobject W to be processed. Accordingly, the present embodiment solves theproblem mentioned above and can elongate the service life of the lamp130 and the lamp driver 310. Moreover, the lamp 130 is controlled withinthe halogen cycle temperature range, which also contributes to theelongation of the service life of the lamp 130.

It should be noted that the cooling pipe 149 is provided for cooling thelamp 130, which facilitates to maintain the lamp 130 within the halogencycle temperature range by a control cooperating with the lamp driver130. Moreover, the present embodiment does not exclude the use of eitherthe method of controlling the temperature of the lamp 130 or the methodof controlling the temperature of the lamp 130 by the lamp driver 310.

The control part 300 controls a rotational speed of the object W to beprocessed by sending a drive signal to the motor driver 320 at apredetermined timing. The control part 300 also feedback-controls theoutput of the lamp 130 by recognizing the temperature of the lamp 130 incooperation with the temperature control system.

The gags introducing part 180 includes a gas source, a flow adjustvalve, a mass-flow controller, a gas supply nozzle and a gas supplypassage interconnecting the aforementioned (not shown in the figure) soas to introduce a gas used for heat treatment into the process chamber110. It should be noted that although the gas introducing part 180 isprovided to the sidewall 112 of the process chamber 110 so as tointroduce the gas into the process chamber from the side, the positionof the as introducing part 180 is not limited to the side of the processchamber. For example, the gas introducing part 180 may be constituted asa showerhead, which introduces the process gas from an upper portion ofthe process chamber 110.

If the process to be performed in the process chamber 110 is anannealing process, the process gas includes N₂, Ar, etc.; if the processis an oxidation process, the process gas includes O₂, H₂, H₂O, NO₂, etc;if the process is a nitriding process, the process gas includes N₂, NH₃,etc.; if the process is a film deposition process, the process gasincludes NH₃, SiH₂, Cl₂, SiH₄, etc. It should be noted that the processgas is not limited the above-mentioned gasses.

The mass-flow controller is provided for controlling a flow of theprocess gas. The mass-flow controller comprises a bridge circuit, anamplification circuit, a comparator control circuit, a follow adjustvalve, etc. so as to control the flow adjust valve by measuring a gasflow by detecting an amount of heat transmitted from the upstream sideto the downstream side in association with the gas flow. The gas supplypassage uses a seamless pipe and a bite-type coupling or a metal gasketcoupling so as to prevent impurities from entering the gas to besupplied. Additionally, the supply pipe is made of a corrosion resistantmaterial so as to generation of dust particles due to dirt or corrosionon an inner surface of the supply pipe. The inner surface of the supplypipe may be coated by an insulating material such as PTFE (Teflon), PFA,polyimide, PBI, etc. Additionally, the inner surface of the supply pipemay be subjected to an electropolishing. Further, a dust particle filtermay be provided to the gas supply passage.

In the present embodiment, although the exhaust part 190 is providedparallel to the gas introducing part 180, the position and the numberare not limited to that shown in the figure. The exhaust part 190 isconnected to a desired exhaust pump, such as a turbomolecular pump, asputter ion pump, a getter pump, a sorption pump, a cryostat pump,together with a pressure adjust valve. It should be noted that althoughprocess chamber is maintained at a negative pressure environment in thepresent embodiment, such a structure is not an essential feature of thepresent invention. That is, for example, the process chamber may bemaintained at a pressure ranging from 133 Pa to an atmospheric pressure.The exhaust part 190 has a function to exhaust helium gas beforestarting a subsequent heat treatment.

A description will now be given, with reference to FIG. 2, of a rotatingmechanism of the object (wafer) W to be processed. In order to maintaina good electric characteristic of each element in an integrated circuitand a high yield rate of products, a uniform heat treatment is requiredover the entirety of the surface of the object W to be processed. If atemperature distribution on the surface of the wafer W is uneven, theRTP apparatus 100 cannot provide a high-quality heat treatment since athickness of a film produced by a film deposition process may vary and aslip may be generated in the wafer W due to a thermal stress.

The uneven temperature distribution on the surface of the object W to beprocessed may be caused by an uneven irradiance distribution or may becaused by a process gas, which is supplied near the gas introducing part180, absorbing heat from the surface of the wafer W. The rotatingmechanism rotates the object W to be processed, which enables a uniformheating by the lamps 130 over the entire surface of the object W to beprocessed.

The rotating mechanism of the object W to be processed comprises thesupport ring 150, the permanent magnet 170, a ring-like magnetic member172, a motor driver 320 and a motor 330.

The support ring 150 has a ring shape and is made of a heat resistantceramic such as SiC. The support ring 150 serves as a placement stage onwhich the object W to be processed is placed. The support ring 150supports a periphery of the backside of the object W to be processed. Ifnecessary, the support ring 150 may be provided with an electrostaticchuck or a clamp mechanism so as to fix the wafer to the support ring150. The support ring 150 is configured and arranged to prevent heatform being released from an outer edge of the object W to be processedso that the uniform heating of the wafer W is not deteriorated.

The support ring 150 is connected to the support part 152 at outer endthereof. If necessary, a heat insulating member formed on quartz glassis interposed between the support ring 150 and the support part 152 soas to thermally protect the magnetic member 172. In the presentembodiment, the support part 152 is formed as an opaque quartz memberhaving a hollow cylindrical shape. The bearing 160 is fixed to thesupport part 152 and the inner wall of process chamber 110 so as toallow a rotation of the support part 152 while maintaining the negativepressure environment of the process chamber 110. The magnetic member 172is attached to the lower end of the support part 152.

The ring-like permanent magnet 170 and magnetic member 172, which areconcentrically arranged, are magnetically coupled with each other, andthe permanent magnet 170 is rotated by the motor 330. The motor 330 isdriven by the motor driver 320, which is controlled by the control part300.

Consequently, when the permanent magnet 170 rotates, the magneticallycoupled magnetic member 172 is rotated together with the support part152, which results in rotation of the support ring and the object W tobe processed. Although the rotation speed in the present embodiment is90 r.p.m., the rotation speed may be determined based on a material andsize of the object W to be processed and a type and temperature of theprocess gas so that there is less effect of turbulence of gas within theprocess chamber 110 and stream of gas due to the rotation of the objectW to be processed. The permanent magnet 170 and the magnetic member 172may be reversed as long as they are magnetically coupled, or themagnetic member 172 may also be formed of a permanent magnet.

A description will now be given of an operation of the RTP apparatus100. First, the object W to be processed is carried in the processchamber 110 through a gate valve (not shown in the figure) by aconveyance arm of a cluster tool (not shown in the figure). When theconveyance arm supporting the object W to be processed reaches above thesupport ring 150, a lifter pin vertically moving system moves lifterpins (for example, three lifter pins) upward so as to protrude thelifter pins from the support ring 150 to support the object W to beprocessed. As a result, the wafer is transferred from the conveyance armto the lifter pins, and, then, the conveyance arm returns out of theprocess chamber 110 through the gate valve. Thereafter, the gate valveis closed. The conveyance arm may return to a home position (not shownin the figure).

The lifter vertically moving mechanism retracts the lifter pins belowthe surface of the support ring 150, thereby placing the object W to beprocessed on the support ring 150. The lifter pin vertically movingmechanism may use a bellows so as to maintain the negative pressureenvironment in the process chamber 110 and prevent the atmosphere insidethe process chamber 110 from flowing out of the process chamber 110during the vertically moving operation.

Thereafter, the heat treatment apparatus 100 carries out heat treatment.FIG. 25 is a flowchart of an operation to drive the lamps 130. Referringto FIG. 25, the control part 300 drives the lamp driver 310 in step 1000so as to supply an electric power to the lamps 130 in step 1005. Inresponse, the control part 300 further increases, in step 1010, theelectric power supplied to the lamps 130 through the lamp driver 310.Then, the control part 300 determines, in step 1015, whether or not thetemperature of the lamps 130 (the temperature of the light-emitting part136) is 900° C. After the temperature of the lamps 130 reaches 900° C.,which is an upper limit value of the halogen cycle, the control part 300maintains, in step 1025, the value of the electric power to the lamps130 through the lamp driver 310 by setting an increasing rate of thesupplied electric power to zero. Thereby, the object W to be processedis heated by the radiation of the lamps 130. The control part 300determines, in step 1030, whether or not the object W to be processed isat a predetermined temperature, for example, 800° C. After thetemperature of the object W to be processed reaches 800° C., the heattreatment apparatus 100 carries out a predetermined heat treatment instep 1032. It should be noted that if the temperature of the object W tobe processed reaches the predetermined temperature before thetemperature of the lamps 130 reaches 900° C., the routine immediatelyproceeds to step 1032 so as to carry out the heat treatment.

A heat ray (radiation light) emitted by the lamps 130 is irradiated ontothe surface of the object W to be processed by passing through thequartz window 120 so as to rapidly heat the object W to be processed at800° C. Generally, a periphery of the object W to be processed tends torelease a greater amount of heat than the center portion thereof.However, the lamps 130 of the present embodiment can provide a highdirectivity and temperature control capability by the concentricallyarranged lamps 130 a and 130 b.

Thereafter, the control part 300 controls the temperature control systemso as to cool the lamps 130. That is, the control part 300 carries out afeedback control in accordance with information from a thermometer (notshown in the figures) so as to control the temperature of the coolingpipe 149 a so that the temperature of the seal part 143 c falls in arange from 250° C. to 350° C., preferably at 300° C. FIG. 26 is aflowchart of a control operation for cooling the lamps 130. Referring toFIG. 26, the control part 300 measures the temperature of the seal part143 c in step 1500. The control part 300 determines, in step 1505,whether or not the temperature of the seal part 143 c is equal to orless than 350° C. If the temperature of the seal part 143 c is equal toor less than 350° C., the routine proceed to step 1510 to start coolingthe cooling the seal part 143 c by using the cooling pipe 149 a. Then,the control part 300 measures, in step 1515, the temperature of the sealpart 143 c, and determines, in step 1520, whether or not the temperatureof the seal part 143 c is equal to or less than 250° C. If thetemperature of the seal part 143 c is equal to or less than 250° C., thecooling operation is stopped in step 1525, and otherwise the coolingoperation is continued until the temperature reaches 250° C. Thus, thetemperature of the seal part 143 c is maintained within a range from250° C. to 350° C. by repeating the above-mentioned process.

Similarly, a temperature of the light-emitting part 136 is controlled bythe process of steps 1530 through 1555. That is, the temperature of thelight-emitting part 136 is controlled to fall within a range from 800°C. to 900° C., preferably at 850° C., by adjusting the temperature ofthe cooling pipe 149 b. Such a control prevents oxidation of molybdenumconstituting the electrodes 133 of the electrode part 132 of the lamp130. Additionally, the light-emitting part 136 of the lamp 130 iscontrolled within the halogen cycle. Consequently, the factors causing adamage of the lamp 130 is eliminated, and elongation of the service lifeof the lamp 130 can be achieved.

At the same time the control part 300 controls the motor driver 320 tosend an instruction to drive the motor 330. In response to theinstruction, the motor driver 320 drives the motor 330 so as to rotatethe ring-like magnet 170. As a result, the support part 152 (or 152A)rotates, and the object W to be processed rotates together with thesupport ring 150. Since the object W rotates, the temperature within thesurface of the object W to be processed is maintained uniform during theheat treatment process.

During the heating, the window 120 provides some advantages since theplate 121 of the window 120 has a relatively small thickness and a highthermal conductivity. The advantages includes:

1) thermal spots hardly occurs in the object W to be processed since thewindow 120 uniformly transmits a light from the lamp 130;

2) the irradiation efficiency to the wafer W is not deteriorated sincethe quartz window 120 having the reduced thickness absorbs less heat;

3) a thermal stress fracture hardly occurs since the temperaturedifference between the front and back surfaces of the plate 121 issmall;

4) in a case of a film deposition process, a deposition film andbyproduct are hardly formed on the surface of the plate 121 since atemperature rise in the surface of the plate 12 e is small; and

5) a pressure difference between the negative pressure in the processchamber 110 and the atmospheric pressure can be maintained even if thethickness of the plate 121 is small since the mechanical strength of thewindow 120 is increased by a high bending strength of translucentceramics.

The temperature of the object W to be processed is measured by theradiation thermometer 200, and the control part 300 feedback-controlsthe lamp driver 310 based on the result of measurement. Since the objectW to be processed is rotated, the temperature distribution on thesurface of the object W is supposed to be uniform. However, ifnecessary, the radiation thermometer 200 may measure a temperature at aplurality of points (for example, the center and periphery) on thesurface of the object W to be processed so that the control part 300sends an instruction to change the output of the lamps with respect to aspecific area of the object W when the result of measurement of theradiation thermometer 200 indicates that the temperature distribution onthe surface of the object W to be processed is not uniform.

Returning to the process of FIG. 25, after the object W to be processedis heated at the desired temperature, a process gas is introduced intothe process chamber 110 through the gas introducing part (not shown inthe figure). After the heat treatment (for example, 10 seconds) iscompleted in step 1032, the control part 300 controls the lamp driver310, in step 1035, so as to decrease the electric power supplied to thelamps 130. Then, the lamp driver 310 checks, in step 1040, whether ornot the temperature of the lamps 130 is equal to 250° C. If thetemperature of the lamps 130 is equal to 250° C., the control part 300maintain, in step 1045, the amount of electric power supplied to thelamps 130 by setting the decreasing rate of the electric power to zero.Otherwise, the routine returns to step 1035 to further decrease thetemperature of the lamps 130.

After the heat treatment, the wafer W is carried out of the processchamber 110 by the conveyance arm of the cluster tool through the gatevalve in the reverse sequence. Thereafter, if necessary, the conveyancearm conveys the wafer W to a next stage apparatus such as a filmdeposition apparatus. If the control part receives, in step 1050, aninstruction for a subsequent heat treatment to be performed, the controlpart 300 repeats the above-mentioned process so as to carry out the heattreatment by returning to step 1010. If there is no instruction for asubsequent heat treatment, the power supply to the lamps 130 is stoppedin step 1055, and then the operation of the lamp driver 310 is stoppedin step 1060.

In the above-mentioned series of heat treatment process, the lamp driver310 and the lamps 130 are turned on only once at an initial operation ofthe heat treatment, and the power is not necessarily turned on and offso as to control the temperature of the object W to be processed. Thatis, according to the heat treatment method of the present embodiment, arush current is generated only once, which enables elongation of theservice life of the lamp 130 and the lamp driver 310. Additionally,since the temperature of the lamp 130 is controlled within the halogencycle temperature range, this also contributes the elongation of theservice life of the lamp 130.

Second Embodiment

A description will now be given of a heat treatment apparatus accordingto a second embodiment of the present invention.

The heat treatment apparatus according to the second embodiment of thepresent invention has basically the same structure as theabove-mentioned heat treatment apparatus according to the firstembodiment shown in FIG. 2 except for the lamp 130 provided in theheating unit 140. Thus, descriptions of the entire structure of the heattreatment apparatus according to the second embodiment of the presentinvention will be omitted.

FIG. 27 is a cross-sectional view of a heating unit 140A provided in theheat treatment apparatus according to the present invention. FIG. 28 isan illustrative cross-sectional view of a lamp 130C provided in theheating unit 140A shown in FIG. 27. In FIGS. 27 and 28, parts that arethe same as the parts shown in FIGS. 7 and 9 are given the samereference numerals, and descriptions thereof will be omitted.

The heating unit 140A is provided with a plurality of lamps 130 thatincludes large-diameter lamps 130Ca and small-diameter lamps 130Cb. Thelarge-diameter lams 130Ca correspond to the lamps 130 a shown in FIG. 9,and the small-diameter lamps 130Cb correspond to the lamps 130 b shownin FIG. 10.

Here, the lamp 130 generically represents the lamp 130Ca and the lamp130Cb. In the present embodiment, the heating unit 140A is separatedfrom the object W to be processed so that a distance between theirradiation surface of the lamp 130 and the object W to be processed isset to about 40 mm.

Although the lamp 130 is a single-end type in the present embodiment,other energy source such as an electric wire heater may be used. Here,the single-end type refers to a kind of lamp which has a singleelectrode part 132 as shown in FIG. 28. Although the lamp 130 has thefunction to heat the object W to be processed and is a halogen lamp inthe present embodiment, a lamp applicable to the heating unit 140A isnot limited to a halogen lamp. Moreover, although an output of the lamp130 is determined by the lamp driver 310, the lamp driver 310 iscontrolled by the control part 300 as described later and supplies anelectric power to the lamp 130. It should be noted that in the presentembodiment, the electric power supplied to the lamp 130 is controlled bythe control part 300 so that the power density of the lamp 130 b islarger than the power density of the lamp 130 a. Specifically, the lamp130Cb has a power density two to three times that of the lamp 130Ca.

Typically, the lamp 130 has a single electrode part 132, a middle part134, a light-emitting part 136 connected to the electrode part 132 viathe middle part 134, and a reflector 241. The light-emitting part 136comprises a coil 138 part and a reflector 139. The coil part 138 isprovided to a filament 137 connected to the electrode part 132 via themiddle part 134. In the present embodiment, a thread (external thread)131 is formed on a side of the lamp support part 142, which faces agroove 143 described later. The thread 131 is a triangular screw threadin the present embodiment, and a generally triangle-shaped ridge isformed. It should be noted that the thread 131 is not limited to theabove-mentioned configuration, and may be a square thread or atrapezoidal thread. However, the lamp 130 does not always require thethread 131, and the lamp 130 having no thread may be used.

The electrode part 132 has a pair of electrodes 133 and is connectedwith the lamp driver 310 electrically through the lamp support part 142.The electrodes 133 are electrically connected to the filament 137. Theelectric power supplied to the electrode part 132 is determined by thelamp driver 310, and the lamp driver 310 is controlled by the controlpart 300. A seal part 143 c mentioned later connects between theelectrode part 132 and the lamp driver 310.

The middle part 134 is formed airtight with the light-emitting part 136.Nitrogen, argon or halogen-gas is enclosed within the interior of themiddle part 134. The middle part 134 is a cylinder, which is locatedbetween the electrode part 132 and the light-emitting part 136 and has apredetermined length so as to separate the electrode part 132 and thelight-emitting part 136 from each other. The middle part 134 has anadvantage in that the length thereof is preferable for the temperaturecontrol of the lamp 130 described later. It should be noted that sincethe filament 137 positioned inside the middle part 134 emits a light, itis natural that the filament is a part of the light-emitting part 136.However, in this specification, since the electrode part 132 and thelight-emitting part 136 (the part which emits light most strongly) areseparated by a predetermined distance, this area is defined merelydefined as the middle part 134. In the present embodiment, the middlepart 134 is formed of ceramics. However, the middle part 134 may beformed of a metal other than ceramics, such as aluminum or SUS(stainless steel).

The light-emitting part 136 refers to a part, which emits a light in thelamp 130. The light-emitting part 136 has a side surface configurationsuch as a hemisphere, an ellipse hemisphere or a cylinder, and is formedof quartz or glass. In addition, as mentioned above, the light-emittingpart 136 is formed integral and airtight with the middle part 134, andhalogen gas is enclosed therein.

The light-emitting part 136 has a coil part 138 of a filament 137, whichis a luminescent part, and a reflective means 139 therein. The coil part138 may be any kind of types such as a single coil or a double coil. Theconfiguration of the coil part 138 can also be made into an arbitraryconfiguration such as a parallel arrangement of a plurality of coils.The reflective means 139 is located at a position opposite to the objectW to be processed with respect to the coil part 138 so as to reflect alight emitted from the coil part 138, which travels away from the objectW to be processed in the longitudinal direction of the lamp 130.Furthermore, the reflective means 139 has a configuration having a toplocated along the axial center in the longitudinal direction of the lamp130, such as a cone or a hemisphere.

More specifically, as shown in FIG. 28, the reflective means 139 forms adomal shape, such as a hemisphere, a half-ellipse sphere or a circularcone, in cooperation with a reflective area 242 of a reflector 241described later. By providing the reflective means 139 in the lamp 130,the light which travels toward the middle part 134 of the lamp 130 canbe reflected, and the light can be irradiated efficiently onto theobject W to be processed.

In the present embodiment, a thread 131 is formed on the middle part 134and the electrode part 132 of the lamp 130. The thread 131 can fits tothe groove 143 formed in lamp support part 142 mentioned later.Accordingly, it is preferable that the middle part 134 and the electrodepart 132 of the lamp 130 are formed of a material mentioned above inconsideration with its mechanical strength and machinability. However,the lamp 130 of the present invention is not limited to such a material,and the middle part 134 of the lamp 130 may be a cylindrical memberformed of quartz or translucent ceramics like the light-emitting part136. However, when such a structure is used in the present embodiment, acover must be provided to the lamp 130 so as to provide a mechanicalstrength and machinability. A material of the cover preferably has ahigh thermal conductivity so as not prevent cooling of the lamp 130 asmentioned later.

Reflectors 241 a and 241 b cover the light-emitting parts 136 a and 136b of Lamps 130 a and 130 b respectively, so as to reflect the light ofthe lamp 130 toward the object W to be processed. It should be notedthat the reflector 241 generically represents the reflector 241 a andthe reflector 241 b. The reflector 241 has a cylindrical shape the sameas the groove 143, and a thread (male thread) 144 engageable with thegroove 143 is formed on a side surface which is brought into contactwith an inner surface of the groove 143. As mentioned later, the thread147 engageable with a thread 244 of the reflector 241 is formed on theinner surface of the groove 143, and, thereby, the lamp 130 isdetachable from the lamp support part 142 together with the reflector241.

The reflector 241 includes the reflective area 142, which reflects thelamp light toward the object W to be processed. The reflector 241 has anopening 243 a for inserting the light-emitting part 136 of the lamp 130into the reflective area 242 and an opening 243 b from which a lamplight is projected. This opening 243 a is formed in a shapesubstantially the same as the light-emitting part 136 of the lamp 130 sothat the light-emitting part 136 of the lamp 130 and the reflector 241are detachably attached. On the other hand, the opening 243 b has thesame configuration as the opening of the reflective area 242 mentionedlater, and the light projected from the coil part 138 of thelight-emitting part 136 is irradiated onto the object W to be processedthrough the opening 243 b.

Moreover, for example, a non-penetrating hole or a protrusion may beprovided to a bottom surface of the cylindrical reflector 241 so as tofacilitate detachment of the reflector 241. It should be noted thatalthough the reflector 241 has the opening 243 a so as to be detachableattached to the light-emitting part 136 of the lamp 130 and the lampsupport part 142 in the present embodiment, the reflector 241 may beformed integrally with the light-emitting part 136. In the presentembodiment, the body of the lamp including the light-emitting part 136and the reflector 241 can be detachable attached individually, therebyincreasing convenience of attachment and detachment of the lamp 130 asmentioned later.

The reflective area 242 has a domal shape such as a convex whichprotrudes away from the object W to be processed so as to cover thelight-emitting part 136 of the lamp 130. It should be noted that it isimpossible for the reflective area 242 to form a perfect domal shape dueto presence of the opening 243 a. However, the reflective area 242 ofthe reflector 241 can form a substantially perfect domal shape incooperation with the reflective means 139 of the lamp 130 as mentionedabove. Therefore, the opening 243 a does not become a factor, whichgenerates a reflective loss of the lamp 130. It should be noted that thereflective means 139 of the lamp 130 can also be interpreted as a partof the reflector 241.

More specifically, the domal shape may be formed in a hemisphereconfiguration so that the light projected from the coil part 138 maytravel toward the opening 243 b of the reflector by efficientlyreflected, preferably by one time reflection. The configuration of thereflector 241 may not be limited to a hemisphere configuration, but maybe in other configurations, if the above-mentioned action and effect canbe achieved. For example, the reflective area 242 may have a shape of ahalf-ellipse globular form or a circular cone.

The reflective area 242 is formed of aluminum (Al). Since the surface ofthe reflective area 242, which covers the coil part 138, is coated by ahigh-reflectance film so as to efficiently reflect a light including avisible light and an infrared light. As a material of the coating,nickel (Ni), gold (Au) or rhodium (Rh) is preferably used. As a methodof coating, it is preferable to carry out the coating by plating Ni andAu on an aluminum material or plating Ni, Au, Rh and Au on an aluminummaterial sequentially in that order.

The reflector 241 has the function to reflect a light emitted by thecoil part 138 of the filament 137 by the reflective area 242 and thereflective means 139 of the lamp 130, and also has a function to improvethe directivity of the lamp 130. More specifically, the reflectorefficiently reflects the light emitted by the coil part 138 of thefilament 137 by the domal shape formed by the reflective area 242 andthe reflective means 139 of the lamp 130, preferably with one timereflection, and irradiates the reflected light onto the object W to beprocessed, and also converges the light in a direction substantiallyperpendicular to the surface of the object W to be processed. That is,the light emitted by the lamp 130 is concentrated into a range in thetangential direction of the opening 243 b of the reflector 241. Thus,since there is little number of times of reflection by the reflector139, the light emitted by the lamp 130 of the present embodiment reachesthe object W to be processed, with little energy loss, and has excellentdirectivity.

Conventionally, there is a problem in that the energy of light decreasesdue to a reflective loss associated with a multiple reflection of thereflector. The present embodiment eliminates such as problem. Therefore,since the irradiation efficiency of the lamp 130 with respect to theobject W to be processed can be higher than the conventional lamp, ahigh-speed temperature rise can be attained with a low powerconsumption. It should be noted that a radius of curvature and theconfiguration of the opening of the reflector 241 may be changeddepending on a directivity required to the lamp 130.

Referring to FIGS. 6 and 27, the lamp support part 142 which functionsas a lamp house with has a substantially rectangular parallelepipedshape, and has the grooves (holes) 143 which contain the respectivelamps 130C and isolation wall 148. Each groove 143 serves as a lampaccommodation part which accommodates the lamp, and comprises a groove143 a which accommodates the lamp 130Ca and a groove 143 b whichaccommodates the lamp 130Cb. It should be noted that the groove 143generically represents the grooves 143 a and 143 b. The configuration ofthe groove 143 will be described later, and a description will be givenbelow of an arrangement of the grooves 143.

As shown in FIG. 6, the groove 143 a is formed along concentric circlesarranged in an area from the center of the lamp support part 142 (aposition corresponding to the center of the object W to be processed) tothe vicinity of the support ring 150 in a radial direction. Morespecifically, a plurality of grooves 143 a are formed along theconcentric circles of which radius is increased by a first distance fromthe center so that the center of each of the grooves 143 a is positionedon the corresponding concentric circles. The first distance is set toabout 0.5 to 1.5 times a half-value width of a radiation distribution.The half-value width corresponds to a width of the radiationdistribution when an intensity of the light of the lamp 130Ca is onehalf of a peak value. In the present embodiment, the lamp 130Ca showsthe half-value width of about 40 mm in a direction of radiation of thelamp light at a point about 40 mm from the projecting surface 136 b. Thedistance of 40 mm corresponds to the distance between the lamp 130 andthe object W to be processed. It should be noted that the half-valuewidth differs from lamp to lamp, and the present invention is notlimited to this value. Moreover, in the present embodiment, since thecooling pipe 149 mentioned later is provided in the light-emitting-part136, the first distance is set to 50 mm (1.25 times the half-valuewidth) which is a lager value than the diameter of the light-emittingpart 136 of the lamp 130Ca. It should be noted that the concentriccircles may be extended to the location at which the concentric circlesdo not overlap with a groove 143 b mentioned later. Moreover, it ispreferable that an interval between the grooves 143 a arranged along oneof the concentric circles be set equal to the first distance.

On the other hand, the grooves 143 b are formed along a plurality ofconcentric circles within and in the vicinity of an area where thesupport ring 150 overlaps with the object W to be processed. Morespecifically, the grooves 143 b are arranged along first, second andthird circles C1, C2 and C3. The first circle is located within the areawhere the support ring 150 overlaps with the object W to be processed.The second circle C2 has a radius larger than the radius of the firstcircle by a second distance. The third circle C3 has a radius smallerthan the radius of the first circle by the second distance.

It should be noted that the second distance is set to about 0.5 to 1.5times the half-value width of a radiation distribution of the lamp130Cb. The lamp 130Cb shows the half-value width of about 20 mm in adirection of radiation of the lamp light at a point about 40 mm from theprojecting surface 136 b. In the present embodiment, the distance of 40mm corresponds to the distance between the lamp 130C and the object W tobe processed. It should be noted that the half-value width differs fromlamp to lamp, and the present invention is not limited to this value.Moreover, similar to the grooves 143 a, since the cooling pipe 149mentioned later is provided in the light-emitting-part 136, the seconddistance is set to 25 mm (1.25 times the half-value width). Moreover, itis preferable that an interval of the grooves 143 b along one of thecircles be set equal to the second distance.

In the present embodiment, although the grooves 143 b are formed alongthe three circles C1, C2 and C3, the number of circles is not limited tothree and may be changed to an appropriate value. As mentioned above,the grooves 143 b are formed so that the lamps 130Cb can irradiate thearea where the support ring 150 and the object W to be processed overlapwith each other. For example, when the object W to be processed islarger than the circle C2, additional grooves 143 b may be arrangedalong a circle having a diameter larger than the diameter of the circleC2 by a length equal to the second distance. Similarly, when the supportring 150 is smaller than the circle C3, additional grooves 143 b may bearranged along a circle having a diameter smaller than the diameter ofthe circle C3 by a length equal to the second distance.

In the structure mentioned above, the lamp support part 142 enablesarrangement of the lamps 130Ca at the positions in the vicinity of theobject W to be processed and the lamps 130Cb in the part where a supportring 150 overlaps with the object W to be processed and in the vicinityof the part concerned. If the lamp 130C irradiates in the state shown inFIGS. 22 and 23, a greater irradiation area can be obtained by the lamps130Ca in the center of the object W to be processed. On the other hand,a smaller irradiation area can be obtained by the lamps 130Cb in thevicinity of the outer end of the object W to be processed.

In the present embodiment, it becomes possible to irradiate efficientlythe small area where the support ring 150 and the end of the object W tobe processed overlap with each other by arranging the small-diameterlamps 130Cb around the lamps 130Ca. Moreover, as mentioned above, theelectric power supplied to the lamp 130Cb is larger than the electricpower supplied to the lamp 130 a. That is, an energy irradiated by thelamps 130Cb per unit area is greater than that of the lamps 130Ca.According to the arrangement of lamps in the conventional heat treatmentapparatus, it is impossible to control the lamp irradiation areaseparately between the center area and the end area of the object W tobe processed since only one kind of lamp is used.

The specific heat differs from the support ring 150 to the object W tobe processed. Specifically, the specific heat of the support ring 150 issmaller than the specific heat of the object W to be processed.Therefore, there is a problem in that the a temperature siring rate ofthe area where the support ring 150 overlaps with the object W to beprocessed and the area in the vicinity of the area concerned is smallerthat other areas of the object W to be processed. However, in thepresent embodiment, since the small area in the periphery of the objectW to be processed is irradiated by the small-diameter lamps 130Cb, theobject W to be processed can be efficiently heated.

Furthermore, the center area and the peripheral area of the object W tobe processed are prevented from being heated unevenly, which results ina high-quality heat treatment process. Moreover, using thelarge-diameter lamps 130Ca in the vicinity of the center of the object Wprovides a large irradiation area by one of the lamps 130Ca. Therefore,the number of the lamps 130C in the vicinity of the center can besmaller than conventional one, which allows a reduction in the powerconsumption. In the present embodiment, the above-mentioned problem issolved by using the lamps 130Ca and 130Cb having different diameters andvarying an electric power supplied to the lamps 130Ca and 130Cb.

Similar to the lamps 130C in the first embodiment, the lamps 130Cb maybe inclined so that the lights irradiated by the adjacent lamps 130Cblocated in the outermost area in a radial direction overlap with eachother on the object W to be processed.

It should be noted that the arrangement of the grooves 143 is notlimited to the concentric arrangement, and other arrangements such as,for example, a linear arrangement or a spiral arrangement may be used ifsuch an arrangement satisfies the above-mentioned conditions. Moreover,in the present embodiment, since the opening configuration of thereflector 241 of the lamp 130C is circular, the irradiationconfiguration of the lamp light is circular. However, the lamp 130C doesnot have limitation in the irradiation configuration in view of theconcept that the lamps having a large irradiation area located in thecenter of object W to be processed and the lamps having a smallirradiation area are located in the peripheral area of the object W tobe processed. For example, the configuration of the lamp 130C and/or thereflector 241 may be changed so that the irradiation area becomes atriangle. In addition, the configuration of the lamp light may not belimited to a triangle but may be other polygons such as a square orhexagon. Moreover, any irradiation approaches, which can provide similareffect, may be used.

A description will now be given of the configuration of the groove 143.The groove 143 has the same configuration as the lamp 130C, andcomprises a part 143 c which accommodates the electrode part 132 of thelamp 130C, a part 143 d which accommodates the middle part 134 and apart 143 e which accommodates the light-emitting part 136. The part 143c connects the electrode part 132 to a lamp driver 310 shown in FIG. 2,and serves as a seal part, which gives a seal between the electrode part132 and the lamp driver 310.

The groove 143 has a thread (female screw) 147 formed on an innersurface contacting the lamp 130C. In the present embodiment, the thread147 is a triangular screw thread, which matches the thread formed on thelamp 130C. It should be noted that the shape of the thread profile isnot limited to the triangular profile, and if the thread 131 of the lamp130C is a square screw or a trapezoidal screw thread, the thread 147 ofthe groove 143 is also formed to correspond to the thread 131 of thelamp 130C. In addition, the groove 143 is formed so that the thread 147optimally fits to the thread of the lamp 130C when the lamp 130 expandsthermally. That is, when the lamp 130C is not thermally expanded, theouter and inner diameter and the pitch of the thread 147 formed in thegroove 143 are slightly larger than that of the thread 131 formed on thelamp 130C. However, the difference between the dimensions of the threadsis such that insertion of the lamp 130C and engagement with the groove134 are not prevented.

In the above-mentioned structure, the groove 143 and the lamp 130C havea relationship of a nut and a bolt. The lamp 130C can be attached to thegroove 143 by inserting the lamp support part 142 into the groove 143while rotating so as to engage the threads with each other. When thelamp 130C is in a normal state where the lamp 130 does not expandthermally, the threads of the lamp 130C and the groove 143 engages witheach other at surfaces in the direction of gravity. That is, a contactarea is maintained between the lamp 130C and the groove 143. Althoughsuch a contact area is necessary to retain the lamp 130C, there is aproblem as mentioned below. The groove of the lamp support part of theconventional lamp has the same cylindrical shape with the lamp to beinserted into the groove. The groove is formed so that, when the lampthermally expands and becomes a maximum size, the lamp completely fitsin the groove. That is, in the conventional structure, when the lamp isnot completely expanded, the cooling effect of the cooling pipe, whichis provided in the lamp support part to cool the lamp, deterioratessince the contact area between the lamp and the groove is small. Thepresent embodiment eliminates such a problem. Moreover, since the ridgeof the thread 147 of the groove 143 is slightly larger than the ridge ofthe thread 131 of the lamp 130C, there is formed a small space betweenthe groove 143 and the lamp 130C. The groove 143 and the lamp 130C areconfigured to fit with each other when the lamp 130C is heated andexpanded thermally so that the small space permits the thermal expansionof the lamp 130C within the groove 143.

Furthermore, the configuration of the lamp 130C and the configuration ofthe groove 143 have the following advantages. If an output of a part ofthe lamps is increased, the part of the lamps may degrade faster.Moreover, the reflector also degrades faster if a larger power issupplied to the lamp. Therefore, a high-output lamp has a shorterservice life than a low-output lamp. Similarly, the reflector for thehigh-output lamp has a shorter service life than a reflector for thelow-output lamp. This is for the reason that the temperature inside thehigh-output lamp is high, which causes the aluminum coating material andthe base metal forming the reflector 241 diffusing each other resultingin formation of an alloy. Such an alloy causes degradation of thereflectance of the aluminum coating material. Accordingly, the servicelife of the reflector 241 b is shorter than the reflector 241 a.

Consequently, in order to exchange the lamp and reflector of whichservice life has expired located in the peripheral area of the lampsupport part, it is required to exchange the entire lamp support partincluding the lamps and reflectors which area still usable, which is notan economical way. However, in the present embodiment, the groove 143and the lamp 130C of the lamp support part 142 have a relationship of anut and a blot as mentioned above, and, thereby, the lamp 130C and thereflector 241 can be removed on an individual lamp and reflector basis.

Therefore, the usable lamps 130C can be continuously used by replacingonly degraded lamps 130C. Thus, the present embodiment solves theabove-mentioned problem by constituting the lamps being easilyreplaceable on an individual lamp basis. Additionally, in the presentembodiment, since the reflector 241 is detachable attached to the lamp130C, the lamp 130 and/or the reflector 241 may be replacedindividually. Thus, the present embodiment eliminates a replacement workof the entire lamp support part, which is complex and inconvenient, and,thus, there is a further advantage that the maintenance efficiency isimproved.

It should be noted that the above-mentioned configuration of the lamp130C is only an example, and any configuration may be adopted if thelamp 13A and the reflector 241 can be replaced either in combination orsingular. Additionally, the reflector 242 bay be connected to the lampsupport member 142 by connecting members such as screws as shown in FIG.31. FIG. 31 is a cross-sectional view of a reflector 241 c, which is avariation of the reflector 241 shown in FIG. 29. FIG. 32 is a plan viewof the reflector 241 c shown in FIG. 31. The reflector 241 c has thereflective area 242 a, and has an opening 243 c and an opening 243 d.The opening 243 c is provided for inserting the light-emitting part 136of the lamp 130C therethrough, and the opening 243 d is provided forprojecting a light therethrough. A flange 245 is provided on the side ofthe opening 243 c, and through holes 245 a are provided in the flange245. The reflector 241 c is mounted to the lamp support part 142 byscrews via the through holes 245 a.

As shown in FIGS. 6 and 27, the isolation wall 148 is arranged betweenthe adjacent grooves 143 which are arranged along the concentriccircles. In the present embodiment, the thickness of the isolation wall148 between the parts 143 c is about 50 mm, and the thickness of theisolation wall between the parts 143 e is about 10 mm. Moreover, thethickness of the isolation wall between the parts 143 c of groove 143 bis about 15 mm, and the thickness of the isolation wall between theparts 143 e is about 5 mm. The isolation wall 148 is provided with apair of cooling pipes (cooling water pipes) 149 a and 149 b. Hereinaftera cooling pipe 149 generically represents the cooling pipes 149 a and149 b. More specifically, the cooling pipe 149 a is located in the placecorresponding to the electrode part 132 of the lamp 130C, and thecooling pipe 149 b is located in the place corresponding to thelight-emitting part 136 of the lamp 130C.

The cooling pipe 149 is connected to the temperature-control devicewhich is not shown in the figure. The temperature-control devicecomprises the control part 300, a temperature sensor or thermometer anda heater. A cooling water is supplied to the temperature-control devicefrom a water source such as a water line. Instead of the cooling water,other coolants such as alcohol, gurden, chlorofluorocarbon, etc. may beused. As for the temperature sensor, a well-known sensor such as, forexample, a PTC thermistor, an infrared sensor or a thermocouple may beused. A temperature sensor or thermometer measures a temperature of theinner wall of the electrode part 132 and the light-emitting part 136 ofthe lamp 130C. A heater is constituted by a wire heater wound on anouter surface of the cooling pipe 116. By controlling the magnitude ofthe current, which flows through the wire heater, the temperature of thewater flowing through the cooling pipe 149 can be adjusted.

When the electrodes 133 are made of molybdenum, in order to preventdestruction of the electrodes 133 and seal part 143 c due to oxidizationof molybdenum, the cooling pipe 149 a maintains the temperature of theseal part 143 c at 350° C. or less. Moreover, the cooling pipe 149 bmaintains the temperature of the light-emitting part 136 at 250° C. to900° C. so that the middle part 134 and the light-emitting part 136maintain a halogen cycle. In the halogen cycle, the tungsten whichconstitutes the filament 137 evaporates and reacts with halogen gas, atungsten-halogen compound is generated which floats inside the lamp130C. When the lamp 130C is maintained at 250° C. to 900° C., thetungsten-halogen compound maintains the floating state.

However, when the tungsten-halogen compound is carried to the vicinityof the filament 137 by convection, the tungsten-halogen compound isdecomposed into tungsten and halogen gas due to the high-temperature ofthe filament 137. Then, the tungsten is deposited on the filament 137and the halogen gas repeats the same reaction. It should be noted that,generally, if the temperature exceeds 900° C., devitrification (aphenomenon in which the light-emitting part 136 becomes white) mayoccur. On the other hand, if the temperature is below 250° C.,blackening (phenomenon in which the tungsten-halogen compound adheres tothe wall of the lamp 130, and becomes black) may occur. Further,molecules of the coating material of the reflective area 242 may form analloy with a base metal by being mutually diffusing under a hightemperature, which results in degradation of the reflectance of thereflective area 242. Thus, it is necessary to maintain the reflectorbelow a predetermined temperature. For example, if Ni plating isprovided, the predetermined temperature is preferably 300° C.

In the present embodiment, the cooling pipe 149 a is maintained at atemperature within the range of halogen cycle and which can preventoxidization of molybdenum. Such a temperature preferably ranges from250° C. to 350° C. Additionally, the cooling pipe 149 b is maintained ata temperature within the range of halogen cycle and also a temperatureat which the coating layer is prevented from diffusion. Such atemperature preferably ranges from 250° C. to 300° C.

It should be noted that instead of providing the isolation wall 148between parts corresponding to the reflector 241 and the light-emittingparts 136 of the lamps 130C, the space provided with the isolation wall148 may be empty so as to carry out air cooling for the light-emittingparts 136. The air cooling may be carried out by a known cooling systemsuch as a blower, which carries out forced air cooling. Furthermore,another cooling method in which a common cooling pipe is provided so asto cool both the reflector 241 and the light-emitting part 136 may beused. In such a method, the cooling pipe may be cooled at a temperatureof 250° C. to 300° C., which is a temperature common to both theprotection of the coating and the halogen cycle range. Even with theabove-mentioned structure, the same effect as the above-mentionedcooling pipe 149 can be acquired.

Next, a radiation thermometer 200 is explained with reference to FIGS.2, 33 and 34. FIG. 33 is an illustrative enlarged cross-sectional viewof the radiation thermometer 200 and parts of the process chamber 110 inthe vicinity of the radiation thermometer 200. FIG. 34 is anillustrative enlarged cross-sectional view of a sensor rod 210 and apart of the radiation thermometer 200 in the vicinity of the sensor rod210.

The radiation thermometer 200 is provided on the opposite side of thelamp 130C with respect to the object W to be processed. However, thepresent invention does not exclude a structure in which the radiationthermometer 200 is provided on the same side with lamp 130C. Theradiation thermometer 200 is attached to the bottom part 114 of theprocess chamber 110. A surface 114 a of the bottom part 114 facing theinterior of the process chamber 110 is provided with gold plating andthe like so as to serve as a reflective plate (high reflectancesurface). This is for the reason that if the surface 114 a is a lowreflectance surface such as black surface, the surface 114 a absorbsheat of the object W to be processed, which results in uneconomical riseof the irradiation output of the lamp 130C.

The bottom part 114 has a cylindrical through opening 115. The radiationthermometer 200 has the sensor rod 210, a filter 220 provided in themiddle of the sensor rod 210 and a radiation detector 230 to which thesensor rod 210 is connected. An end of the sensor rod 210 protrudes intothe process space within the process chamber 110 through the throughhole 115. The sensor rod 210 is inserted into the through hole 115provided in the bottom part 114 of the process chamber 110, and issealed by an O-ring 190. Thereby, the process chamber 110 can maintain anegative pressure environment therein irrespective of the existence ofthe though hole 115.

It should be noted that the temperature measuring method according tothe present embodiment mentioned later can omit a chopper and a motorfor rotating the chopper, and the radiation thermometer adopts a minimumnecessary structure, which is relatively inexpensive. The radiationthermometer 200 measures a temperature of the object W to be processed,and sends the measured temperature to the control part 300. Thereby, aheat treatment can be applied to the object W to be processed at adesired temperature.

The sensor rod 210 is comprised of a single core optical fiber or amulti-core optical fiber. With reference to FIG. 33, one end 214 of thesensor rod 210 is connected to the radiation detector 230 through thefilter 220, and the other end 212 is arranged near the object W to beprocessed. The end 212 has a light-converging action so as to introducea radiation light radiated by the object to be measured into theradiation detector 230. It should be noted that the end 212 of the rod210 may be provided with a condenser lens.

Since an optical fiber is capable of guiding the radiation light to thefilter 220 with almost no attenuation, the optical fiber has anadvantage to provide excellent transmission efficiency. Moreover,flexibility can be provided to a light-guiding path of the sensor rod210, and the degree of freedom of arrangement of the radiationthermometer 200 can be increased. Furthermore, since the body of theradiation thermometer 200 or the radiation detector 230 can be separatefurther away from the object W to be processed, each part of theradiation thermometer 200 is prevented from being deformed due to aninfluence of the temperature of the object W to be processed, therebyachieving a higher measurement accuracy.

However, according to the conventional thermometry approach using theradiation thermometer 200, the end 212 of the sensor rod 210 is locatedin the open space, and the sensor rod 210 is projected from the bottom114 and exists in the internal space of the process chamber 110. In themeasurement performed under such a condition, a factor (so-called astray light) other than the radiation light from the object to bemeasured (object W to be processed) may become noise, which lowers theaccuracy of measurement. Thus, the present inventor considered toimprove the accuracy of measurement by interrupting a stray light bylocating the sensor rod 210 inside a space (closed space) in the objectto be measured, which space is shielded with respect to a stray light.

Specifically, as shown in FIG. 33, the end 212 of the sensor rod 210defines a closed space in cooperation with a shield part 216 having adomal shape and the object to be measured (object W to be processed).The end 212 of the sensor rod 210 is located inside the closed space.The shield part 216 has a U-shaped cross-sectional configuration, andinterrupts a stray light by forming an atmosphere different from theprocess space of the process chamber 110 by sealingly contacting anopening side of the U-shaped cross-sectional configuration with theobject to be measured.

In the present embodiment, although the shield part 216 has the U-shapedcross-section, the present invention is not limited to such aconfiguration. It should be noted that, the shield part 226 ispreferably formed of the same material as the object to be measured. Ifthe object to be measured is made of a material, which easily transmitsa stray light, the stray light must be interrupted by applying ashielding film onto the surface of the shield part 216. With theabove-mentioned construction in which the shield part 216 is formed ofthe same material as the object to be measured, it is prevented todeteriorate the accuracy of measurement due to a radiation lightradiated from a different member. However, the configuration andmaterial of the shield part 216 are not limited to the above-mentioned,and other configurations and materials may be used if a stray light canbe interrupted.

Moreover, as shown in FIG. 34, a cavity into which the sensor rod 210 isinserted may be formed in the object to be measured so as to form aclosed space by inserting the sensor rod 210 into the cavity. Here, FIG.34 is an illustrative cross-sectional view showing another example ofthe configuration of the end 212 end the sensor rod 210 shown in FIG.33. However, with the composition in FIG. 34, it is necessary to form ahole or a cavity in the object to be measured, i.e., the object W to beprocessed. Therefore, such a cavity is preferably provided in theperiphery part of the object W to be processed. Or a cavity may beformed in the support ring 150, and the sensor rod 210 may be insertedinto the cavity so as to measure a temperature of the object W to beprocessed indirectly through the support ring.

Although noise caused by incidence of a stray light is on of factors,which decrease the accuracy of measurement, the stray light isinterrupted in the present embodiment by a forming a differentatmosphere by the shield part 216. Accordingly, a magnitude of influenceof a stray light can be made smaller than arranging the sensor rod 210in an open space. Therefore, it becomes possible to measure thetemperature of the object to be measured with sufficient accuracy, andthe stability and reproducibility of production ability can be raised.Moreover, it is possible to provide a heat treatment with high accuracyand a high-quality wafer which has been subjected to such a highaccuracy heat treatment. Moreover, the sensor rod 210 may be providedwith a moving mechanism.

For example, the temperature measurement of the object W to be processedmay be performed, only when it is needed, by moving and contacting thesensor rod 210 to the object W to be processed, and separating thesensor rod 210 from the object W to be processed when the temperaturemeasurement is not required. If such a structure is adopted, the sensorrod 210 can be prevented from affecting a gas treatment and flocking arotation of the object W to be processed when performing the gastreatment and the rotation of the object W to be processed as mentionedlater. Moreover, the sensor rod 210 may also be prevented from affectingthe gas treatment and blocking the rotation of the object W to beprocessed, by locating the sensor rod 210 within the support ring 150.

Furthermore, in order to investigate the cause of the measurement errorof the radiation thermometer in more detail, the present inventorinvestigated the radiation characteristic of the object W to beprocessed. Then, the present inventor measured emissivity to awavelength with respect to a material used for the object W to beprocessed by setting a temperature as a parameter. The result ofmeasurement showed that there is a wavelength range in which a materialsuch as quartz or silicon carbide shows substantially constant value ofemissivity to wavelength irrespective of the temperature. Moreover, itwas found that the value of the emissivity varies depending on thewavelength.

There may be a large possibility of receiving an influence of noise if aradiation light having a wavelength of a low emissivity (that is, asmall radiation energy) is used when performing a temperaturemeasurement using a radiation thermometer. Conventionally, at the timeof temperature measurement, selection of an appropriate wavelength forimproving the accuracy of measurement is not performed, and, thus, aradiation light containing much noise is used for the measurement.Therefore, the present inventor assumed that such noise causesmeasurement errors, and considered that an accurate temperaturemeasurement can be achieved if a radiation light having a wavelengthproviding a high emissivity is used. Thus, the radiation thermometer 200of the present invention has the filter 220 so as to select a wavelengthsuitable for temperature measurement.

The filter 220 is located between the sensor rod 210 and the radiationdetector 230, and has a function to limit the radiation light introducedinto the radiation detector 230 in accordance with the wavelength. Thefilter 220 can be a wavelength filter produced by a known technique, anddescription thereof will be omitted. In the present embodiment, thefilter 220 selects a wavelength from a wavelength range providing a highemissivity.

FIG. 35 is a graph showing a relationship between emissivity of a quartzboard and wavelength of the radiation light with a temperature and athickness of the quartz board as parameters. FIG. 36 is a graph showinga relationship between emissivity of a silicon carbide (SiC) board andwavelength of the radiation light with a temperature and a thickness ofthe SiC board as parameters. FIG. 37 is a graph showing a relationshipbetween emissivity of an aluminum nitride (AlN) board and wavelength ofthe radiation light with a temperature and a thickness of the AlN boardas parameters.

For example, as interpreted from the graph of FIG. 35, a quartz boardshows a high emissivity in a wavelength range from 4.5 μm to 7.4 μm, anda wavelength range from 9.0 μm to 19.0 μm. By selectively passing alight of a wavelength within the above-mentioned wavelength rangesthrough the filter 220, a radiation light having a wavelength providinga high emissvity, which is known from the graph of FIG. 35, can beintroduced into the radiation detector 230.

In addition, as interpreted from the graph of FIG. 36, an SiC boardshows a high emissivity in a wavelength range from 4.3 μm to 10.5 μm anda wavelength range from 12.5 μm to 20.0 μm. Further, as interpreted fromthe graph of FIG. 37, an AlN board shows a high emissivity in awavelength range from 45.0 μm to 11.0 μm and a wavelength range from17.0 μm to 25.0 μm.

Accordingly, with respect to SiC and AlN, by selectively passing a lightof a wavelength within the above-mentioned wavelength ranges through thefilter 220, a radiation light having a wavelength providing a highemissvity, which is known from the graph of FIG. 36 or 37, can beintroduced into the radiation detector 230.

It should be noted that although the filter 220 is used in the presentembodiment in order to select a wavelength introduced into the radiationdetector 230, the present invention is not limited to a filter and anyknown technique can be used to selectively pass a desired wavelength.Moreover, a plurality of filters 220 may be used as mentioned later.

The radiation detector 230 comprises an image-formation lens, an Siphoto-cell and an amplification circuit, which are not shown in thefigure. The radiation detector 230 converts a radiation light incidenton the image-formation lens into a voltage signal, i.e., an electricsignal representing an intensity of radiation E1(T), and sends theelectric signal to the control part 300. The control part 300 isprovided with a CPU and a memory, and computes a temperature T of theobject W to be processed based on the intensity of radiation E1(T). Itshould be noted that a computation part (not shown) of the radiationthermometer 200 may perform such a computing operation instead of thecontrol part 300.

More specifically, the radiation light is converged at the end 212 ofthe sensor rod 210, and is transmitted to the radiation detector 230through an optical fiber. An intensity of radiation (or luminance) ofthe radiation light transmitted through the sensor rod 210 can berepresented by the following equation (3).E ₁(T)=εE _(BB)(T)  (3)Where, E₁(T) represents an intensity of radiation from an object to bemeasured at a temperature T which is obtained by the radiation detector230, and E_(BB)(T) represents an intensity of radiation of a black bodyat the temperature T. The equation (3) is derivable from Planck'sradiation law.E _(BB)(T)=σT ⁴  (4)where σ is a Stefan-Boltzmann constant which is represented asσ=5.67×10⁻⁸ (W/m² K⁴). The equation (4) is derivable fromStefan-Boltzmann law.

The intensity of radiation E_(BB)(T) can be obtained by substituting theemissivity corresponding to the transmission wavelength of the filter220 for a known object to be measured (the object W to be processed) forepsilon in the equation (3). Therefore, the temperature T can beobtained by substituting E_(BB)(T) for the expression (4). Thus, thecontrol part 300 can obtain the temperature T of the object W to beprocessed.

It should be noted that the above-mentioned temperature measurement isnot limited to measurement of a temperature of the object to beprocessed, and may be used to measure a temperature of the quartz window120. Moreover, a material applicable to the object W to be processed isnot limited to the above-mentioned materials, and any material can beused if the radiation characteristics of the material is know.

FIG. 38 is an illustrative side view of a radiation-thermometer 200A,which is a variation of the radiation thermometer 200 shown in FIG. 2.In the example shown in FIG. 38, a plurality of filters and a pluralityof radiation detectors are provided. The radiation thermometer 200Acomprises optical fibers 210A (optical fibers 210 a through 210 d) eachof which is constituted by a plurality of single core or multi-coreoptical fibers, a filter 220A including a plurality of filters 220 athrough 220 d) and a radiation detector 230A including a plurality ofradiation detectors 230 a through 230 d. The structure of the radiationthermometer 200A is fundamentally the same as the radiation thermometer200, and a detailed description will be omitted.

In the radiation thermometer 200A, similar to the radiation thermometer200, the ends 212A of the plurality of optical fibers 210A are locatedwithin a closed space. The opposite ends 214A (ends 214 a to 214 d) areconnected to the radiation detector 230A through the filter 220A. Itshould be noted that the plurality of filters 220 a through 220 d, whichtogether constitute the filter 220A, selectively passes differentwavelengths of the radiation light introduced into the radiationdetector 230A. It should be noted that each of the filters 220 a through220 d selectively passes a wavelength providing a known high emissivityas mentioned above. Thereby, a plurality of wavelengths each providing aknown high emissivity can be introduced into the radiation detector230A. Thus, the number of radiation lights having different wavelengthscan be increased so as to provide a plurality of detection signals sothat the measurements and other errors are averaged by the control part300, thereby achieving a higher accuracy of measurement than theradiation thermometer 200. It should be noted that signals supplied bythe radiation thermometer 230 may be averaged by a predeterminedcircuit, which is provided between the radiation thermometer 230A andthe control part 300.

Third Embodiment

A description will now be given of a heat treatment apparatus accordingto a third embodiment of the present invention.

The heat treatment apparatus according to the third embodiment of thepresent invention has basically the same structure as theabove-mentioned heat treatment apparatus according to the firstembodiment shown in FIG. 2 except for the lamp 130 provided in theheating unit 140. Thus, descriptions of the entire structure of the heattreatment apparatus according to the third embodiment of the presentinvention will be omitted.

A description will now be given, with reference to FIGS. 39 through 44,of a heating unit 140B provided in the heat treatment apparatusaccording to the third embodiment of the present invention.

FIG. 39 is a bottom plan view of the heating unit 140B provided in theheat treatment apparatus according to the third embodiment of thepresent invention. FIG. 40 is a cross-sectional view of the heating unit140A shown in FIG. 39. FIG. 41 is an illustrative cross-sectional viewof a lamp 130D provided in the heating unit 140B shown in FIG. 39. FIG.42 is an illustrative bottom view of the lamp 130D shown in FIG. 41.FIG. 43 is an enlarged side view of a part of the lamp 130D shown inFIG. 41. FIG. 44 is a circuit diagram of a coil part 138D of a filament137D shown in FIG. 41.

The heating unit 140B is provided with a plurality of lamps 130D thatare supported by the lamp support part 142 so as to serve as a heatsource for heating the object W to be processed.

Although the lamp 130 is a single-end type in the present embodiment,other energy source such as an electric wire heater may be used. Here,the single-end type refers to a kind of lamp which has a singleelectrode part 132D as shown in FIG. 41. Although the lamp 130D has thefunction to heat the object W to be processed and is a halogen lamp inthe present embodiment, a lamp applicable to the heating unit 140B isnot limited to a halogen lamp. Moreover, although an output of the lamp130D is determined by the lamp driver 310, the lamp driver 310 iscontrolled by the control part 300 and supplies an electric power to thelamp 130D. As shown in FIG. 39, in the present embodiment, the lamps130D are arranged so as to correspond to the almost circular object W tobe processed.

Typically, the lamp 130D has a single electrode part 132D, alight-emitting part 134D, a filament 137D connected to the electrodepart 132D and forming a luminescent part and a shield part 139D. Itshould be noted that the configuration of the light-emitting part 134Dis not limited to a cylindrical shape, and other shape may be used.

The electrode part 132D has a pair of electrodes 133D and is connectedwith the lamp driver 310 electrically through the lamp support part 142.The electrodes 133D are electrically connected to the filament 137D. Theelectric power supplied to the electrode part 132D is determined by thelamp driver 310, and the lamp driver 310 is controlled by the controlpart 300. Similar to the first embodiment, the seal part 143 c connectsbetween the electrode part 132D and the lamp driver 310.

The light-emitting part 134D has a cylindrical shape and is connectedairtight with the light-emitting part 134D. Nitrogen, argon or halogengas is enclosed within the interior of the light-emitting part 134D. Thelight emitting part 134D includes a cylindrical side surface 134Da and aprojecting surface 134Db facing the object W to be processed. It shouldbe noted that the projecting surface 134Db is a flat surface, and ispositioned so as to be parallel to the object W to be processed. Thelight-emitting part 134D accommodates the filament 137D and the shieldpart 139D.

With reference to FIG. 41 through FIG. 44, an end of the filament 137Dis connected to one of the electrodes 133D of the electrode part 132D,and the other end is connected to the other electrode 133D. A middlepart of the filament 137D forms a coil part in the lower part of thelight-emitting-part 134D. The filament 137D is a cathode, which emitsthermions (a light) by being electrically heated. In the presentembodiment, the filament 137D is formed of a thin wire of tungsten.However, the filament 137D is not limited to tungsten, and may be formedof other materials.

Hereafter, a part of the filament 137D from the electrode 133 to thecoil part is referred to as a first filament 137Da, and a part of thefilament 137D, which forms the coil part, is referred to as a secondfilament 137Db. It should be noted that, unless it is stated especially,the filament 137D generically represents the first filament 137Da andthe second filament 137Db. The first filament 137Da is a thin wire, andis extended almost linearly from the electrode 133 of the electrode part132 to the second filament 137Db.

On the other hand, the second filament 137Db is made of a thin wire,which forms the coil part. It should be noted that the coils which thesecond filament 137Db forms can be any configuration such as a singlecoil or a double coil, and the present invention does not limit a methodof forming the coil. In the present embodiment, the wire forming thesecond filament 137Db is thinner than the wire forming the firstfilament 137Da. Furthermore, as shown in FIGS. 42 and 44, in the presentembodiment, the second filament 137Db includes a plurality of coilsconnected parallel to each other. However, the arrangement of the coilsis not limited to the parallel connection, and a plurality of coils maybe connected in series as shown in FIG. 45. FIG. 45 is a schematicdiagram showing series-connected coils of the filament 137D.

The plurality of coils form a plane 138D parallel to the projectingsurface 134D. When viewing the lamp 130D from the object W to beprocessed side, an outer configuration of the plane 138D is a circle ora polygon. Although it is preferable that the plane 138D has a sizesubstantially equal to the size of the projecting surface 134D, it issufficient if the plane 138D can be regarded as a surface illuminantwhen the lamp 130D emits a light.

As mentioned above, since the second filament 137Db is thinner than thefirst filament 137Da, a resistance per unit length of the secondfilament 137Db is greater than that of the first filament 137Da.Similarly, the resistance of the second filament 137Db is greater thanthe first filament 137Da since the second filament 137Db forms a coil.When a voltage is supplied to the filament 137D from the electrode part132D, an amount of heat generated in the second filament 137Db is largerthan the first filament 137D. Therefore, the second filament 137Db emitsa light earlier than the first filament 137Da. Moreover, an amount ofheat generated by a unit length of the first filament 137Da is differentfrom that of the second filament 137Db, and only the second filament canemits a light. Therefore, the above-mentioned structure of the first andsecond filaments 137Da and 137Db is capable of emitting a light withsmaller power consumption than a structure in which the first filament137Da and the second filament 137Db have the same thickness.

Furthermore, the second filament 137Db occupies a large area since thesecond filament 137Db is constituted by a plurality of coils. When thelamp 130D is seen from the projecting surface 134Db at the time ofluminescence of lamp 130D, the lamp 130D can be regarded as a surfaceilluminant. Similarly, the heating unit 140 b provided with the lamps130D can also be regarded closer to a surface illuminant than a heatingunit provided with conventional lamps. Therefore, the lamp 130D havingthe filament 137D and the heating unit 140B having the lamps 130D canincrease the irradiation energy more than the conventional heattreatment apparatus.

Furthermore, as mentioned above, the plane 138 where a plurality ofcoils of the second filament 137Db are arranged is formed parallel tothe object W to be processed. Thus, an axis of each of the coils ispositioned parallel to the object W to be processed, and the lightemitted from each coil travels in normal directions of the coil (adirection perpendicular to the axis of the coil). Therefore, at least alight projected from the side of the plane 138D, which faces the objectW to be processed, is directly irradiated onto the object W to beprocessed.

Moreover, since a plurality of coils are present, the energy projectedfrom the light is increased due to a light emitted by one coiloverlapping with a light emitted by adjacent coils, which also providesa sufficient directivity to the light projected from the plane 138D.Therefore, when using the lamp 130D having the filament 137D, reflectivemeans such as a reflector for obtaining the directivity is not needed.There is no multiple reflection by reflector in the lamp 130D, and thereis no reflection loss. Therefore, the light from the lamp 130D isirradiated onto the object W to be processed while maintaining a highenergy.

It should be noted that although the directivity of the lamp 130D isrelated to a side facing the object to be processed via the plane 138D,such a light is shielded by the shield part 139D mentioned later. Itshould be noted that the plane 138D may have a curve configuration likea convex protruding in a direction away from the projection surface134Db of the light-emitting part 134Db. FIG. 46 is an illustrativecross-sectional view of the plane 138D of the lamp 130D shown in FIG. 40and a part in the vicinity of the plane 138D. This configuration of theplane 138D has an action to converge the light projected from the plane138D. Therefore, the directivity of the lamp 130D having the plane 138Dshown in FIG. 46 is improved.

The shield part 139D has almost the same configuration as the planeformed by the second filament 137Db. The shield part 139D is provided onthe side opposite to the projection surface 134Db of the light-emittingpart 134D via the second filament 137Db. The shield part 139D is locatedto overlap with the plane 138 with a gap of several millimeters, forexample, 3 mm to 5 mm. It should be noted that any known method may beused to separately locate the shield part 139D.

The shield part 139D may be fixed to a rod-like member non-electricallyconnected to the electrode part 132D so that the position of the shieldpart 139D is fixed by the rod-like member. The shield part 139D has afunction to shield a light projected from the filament 137Db in adirection opposite to the projection surface 134Db. According to such asshielding function, the lamp 130D can provide the following actions andeffects.

The shield part 139 is heated by the light emitted by the secondfilament 137Db. Thereby, the shield part 139D it self has a radiationaction. According to such a radiation action, the heat-radiation lightprojected from the shield part 139D further heats the second filament137Db. Therefore, such heat may cause luminescence energy of the secondfilament 137Db. That is, the light projected in the direction oppositeto the projection surface 134Da of the light-emitting part 134D via theplane 138D is converted into a light-emitting energy of the secondfilament 137Db. Therefore, by providing the shield part 139D, theheat-radiation light projected from the second filament 137Db can beefficiently used. It should be noted that the shield part 139D accordingto the present embodiment is formed of the same material as the filament137, i.e., tungsten. However, any material can be used for the shieldpart 139D if it has the same action as mentioned above.

The above-mentioned action is obtained by making the diameter of thesecond filament 137Db smaller than the diameter of the first filament137Da and forming the plane 138D by a plurality of coils. When a heattreatment is carried out using the lamp 130D according to the presentembodiment, an irradiation efficiency to the object W to be processedcan be improved and a rapid temperature rise can be achieved at a lowpower consumption. Moreover, the lamp 130D can heat the object W to beprocessed more uniformly than the conventional lamp. That is, ahigh-quality processed object can be provided by applying a heattreatment using the lamp 130. Moreover, since the heating unit 140B doesnot need the reflective means for obtaining directivity, such as areflector, a number of pats of the heat treatment apparatus according tothe present embodiment can be reduced.

A description will now be given, with reference to FIG. 47, of avariation of the lamp 130D according to the present embodiment. FIG. 47is an enlarged cross-sectional view of a part of a lamp, which is avariation of the lamp 130D shown in FIG. 41.

The lamp shown in FIG. 47 has basically the same structure as theabove-mentioned lamp 130 except for the plane 138D. Bordering on adotted line (corresponding to the plane 138D) shown in FIG. 47, a partof the filament 137Db on the side which faces the projection surface134Db is referred to as a first part 137Db-1, and a part of the filament137Db on the side which faces the shield 139D is referred to as a secondpart 137Db-2. In this case, the first part 137Db-1 is formed so as tohave a smaller work function than the second part 137Db-2. Here, thework function represents the minimum energy for taking out electronsfrom inside of a solid in a vacuum through a surface. That is, in thelamp shown in FIG. 47, the first part 137Db-1 emits a light easier thanthe second partial 137Db-2.

More specifically, when the filament 137 is made of a thin wire oftungsten, such a structure can be achieved by covering the first part137Db-1 by a thorium film. The work function of tungsten is 4.52 eV andthe work function of thorium is 2.6 eV. Accordingly, when a voltage isapplied to the filament 137, only the first part 137Db-1, which iscovered by the thorium film having a low work function, can emit alight. Therefore, the supplied energy contributes only to luminescenceof the first part 137Db-1. Thus, 100% of supplied energy can beprojected only from the first part 137Db-1 as luminescence energy.Therefore, it becomes possible to irradiate the high-energy light ontothe object W to be processed as compared with the conventional lamp.Consequently, since the irradiation efficiency to the object W to beprocessed can be improved when a heat treatment is carried out with thelamp shown in FIG. 47, a rapid temperature rise can be attained with alow power consumption. Moreover, it becomes possible to provide anobject, which was subjected to a high-quality process.

In the present embodiment, although thorium is coated on the first part137Db-1, the present invention is not limited to the thorium coating.For example, an oxide film of, for example, barium (Ba), strontium (Sr)or calcium (Ca) may be provided on the first part. Here, the workfunctions of barium oxide (BaO), strontium oxide (SrO) and calcium oxide(CaO) are 1.6 eV, 1.25 eV and 1.6 eV, respectively. Such an oxide filmhas a lower work function than that of tungsten, and an effect the sameas the effect of the thorium film can be provided. Moreover, whenapplying such an oxide film, the filament 137D may be formed ofplatinum, connel alloy, nickel, etc. Namely, the lamp 130D of thepresent embodiment is not limited to the above-mentioned structure, andmay be structured so that the work function of the first part 137Db-1 ofthe filament 137D is lower than that of the second part 137Db-2.Therefore, the lamp 130D of the present embodiment is not limited tothese members, but any structure ma be applicable.

With reference to FIGS. 39 and 40, the lamp support part 140B has agenerally rectangular parallelepiped configuration, and has a pluralityof cylindrical grooves 143 each of which accommodates the lamp 130D andseparation wall 148 between the grooves 143.

Each of the grooves 143 comprises a part 143 a, which accommodates theelectrode part 132D of the lamp 130D, and a part 143 b, whichaccommodates the light-emitting part 134D. The part 143 a connects theelectrode part 132D to the lamp driver 310, and serves to provide a sealbetween the electrode part 132D and the lamp driver 310. The part 143 bhas a diameter greater than a diameter of the part 143 a.

As shown in FIG. 39 the isolation wall 148 is arranged between theadjacent grooves 143 which are arranged along a plurality linesextending in a direction indicated by X in FIG. 39. Within the isolationwall 148, a pair of cooling pipes 149 a and 149 b are arranged in thedirection of X. It should be noted that the cooling pipe 149 genericallyrepresents the cooling pipes 149 a and 149 b. More specifically, thecooling pipe 149 a is located in the vicinity of the electrode part 132Dof the lamp 130D, and the cooling pipe 149 b is located in a positioncorresponding to the light-emitting part 134D of the lamp 130D.

The cooling pipe 149 is connected to the temperature-control devicewhich is not shown in the figure. The temperature-control devicecomprises the control part 300, a temperature sensor or thermometer anda heater. A cooling water is supplied to the temperature-control devicefrom a water source such as a water line. Instead of the cooling water,other coolants such as alcohol, gurden, chlorofluorocarbon, etc. may beused. As for the temperature sensor, a well-known sensor such as, forexample, a PTC thermistor, an infrared sensor or a thermocouple may beused. A temperature sensor or thermometer measures a temperature of theinner wall of the electrode part 132D and the light-emitting part 134Dof the lamp 130D. A heater is constituted by a wire heater wound on anouter surface of the cooling pipe 116. By controlling the magnitude ofthe current, which flows through the wire heater, the temperature of thewater flowing through the cooling pipe 149 can be adjusted.

When the electrodes 133D are made of molybdenum, in order to preventdestruction of the electrodes 133D and the seal part 143 c due tooxidization of molybdenum, the cooling pipe 149 a maintains thetemperature of the seal part 143 c at 350° C. or less. Moreover, thecooling pipe 149 b maintains the temperature of the light-emitting part134D at 250° C. to 900° C. so that the light-emitting part 134Dmaintains a halogen cycle. In the halogen cycle, the tungsten whichconstitutes the filament 137D evaporates and reacts with halogen gas, atungsten-halogen compound is generated which floats inside the lamp130D. When the lamp 130D is maintained at 250° C. to 900° C., thetungsten-halogen compound maintains the floating state.

However, when the tungsten-halogen compound is carried to the vicinityof the filament 137D by convection, the tungsten-halogen compound isdecomposed into tungsten and halogen gas due to the high-temperature ofthe filament 137D. Then, the tungsten is deposited on the filament 137Dand the halogen gas repeats the same reaction. It should be noted that,generally, if the temperature exceeds 900° C., devitrification (aphenomenon in which the light-emitting part 134D becomes white) mayoccur. On the other hand, if the temperature is below 250° C.,blackening (phenomenon in which the tungsten-halogen compound adheres tothe wall of the lamp 130, and becomes black) may occur.

In the present embodiment, the cooling pipe 149 a is maintained at atemperature within the range of halogen cycle and which can preventoxidization of molybdenum. Such a temperature preferably ranges from250° C. to 350° C. Additionally, the cooling pipe 149 b is maintained ata temperature within the range of halogen cycle, preferably at atemperature ranging from 800° C. to 900° C. Although the coolingtemperature for the light-emitting part 134D can be in the range of 250°C. to 900° C., when the cooling efficiency is taken into consideration,the cooling temperature is preferably set to an upper limit temperatureof the halogen cycle since cooling can be carried out with a lesselectric power.

The cooling pipe 149 a is at the common temperature for halogen cycleand oxidization-prevention of molybdenum, and the light-emitting part134D is maintained by the cooling pipe 149 b within the halogen cycletemperature range. Moreover, a temperature slope arises in the lamp 130Ddue to the separate cooling pipes 149 a and 149 b in accordance with thelength of the light-emitting part 134D of the lamp 130D. The temperatureslope (250° C. to 950° C.) maintains the entire lamp 130 within thehalogen cycle temperature range. That is, although there is apossibility that the temperature (800° C. or 950° C.) of thelight-emitting part 136 may influence the temperature (250° C. to 350°C.) of the seal part 143 c if the light-emitting part 134D and the sealpart 143 c are close to each other, such a problem is solved byproviding the light-emitting part 134 in the lamp 130D according to thepresent embodiment.

According to the present embodiment, devitrification and blackening ofthe lamp 130D can be suppressed. Moreover, the electrode part 132D andthe seal part 143 c are prevented form being damaged due to oxidizationof the molybdenum of the electrodes 133D. Furthermore, the lamp 130D iscooled so as to be at a temperature within the halogen cycle temperaturerange. A conventional cooling system of the lamp 130D merely cools theseal part 143 c, and the cooling in accordance with the halogen cycle isnot carried out. Therefore, the cooling pipe 149 according the presentinvention has an advantage of elongating the service life of the lamp130D. It should be noted that the contact area between the groove 30,143 and the lamp 130D is larger than that of the conventional structureas mentioned above, and it is possible to acquire a sufficient coolingeffect.

It should be noted that instead of providing the isolation wall 148between parts corresponding to the light-emitting parts 134D of thelamps 130D, the space provided with the isolation wall 148 may be emptyso as to carry out air cooling for the light-emitting part 134D. Theseal part 143 c shall be cooled by the above-mentioned cooling pipe 149a. Since the light-emitting part 136 is to be cooled at a relativelyhigh temperature of 800° C. to 900° C., the light-emitting part 134D canbe cooled by air cooling so as to obtain the same action and effect asmentioned above. The air cooling may be carried out by a known coolingsystem such as a blower, which carries out forced air cooling.Furthermore, another cooling method in which a common cooling pipe isprovided so as to cool both the isolation wall 148 and thelight-emitting part 134D may be used. In such a method, the cooling pipemay be cooled at a temperature of 250° C. to 350° C., which is atemperature common to both the oxidization prevention of molybdenum andthe halogen cycle range. Even with the above-mentioned structure, thesame effect as the above-mentioned cooling pipe 149 can be acquired.

A description will now be given of the radiation thermometer 200. Theradiation thermometer 200 is provided on the opposite side of the lamp130D with respect to the object W to be processed. Although the presentinvention does not exclude a structure in which the radiationthermometer 200 is provided on the same side with the lamp 130D, it ispreferable that a light from the lamp 130D is prevented from beingincident on the radiation thermometer 200.

The radiation thermometer 200 is attached to a bottom part 114 of theprocess chamber 110. A surface of the bottom part 114 that faces insidethe process chamber 110 serves as a reflective plate (high-reflectancesurface) by being provided with gold plating. This is for the reasonthat is the surface of the bottom part 114 is a low-reflectance surfacesuch as a black surface, the surface absorbs the heat emitted from theobject W to be processed, which uneconomically requires an increase inthe irradiation output of the lamp 130D. The bottom part 114 has acylindrical through hole 115. The radiation thermometer 200 comprises aquartz or sapphire rod, a casing, a chopper or sector, a motor, a lens,an optical fiber and a radiation detector.

The rod according to the present embodiment is made of quartz orsapphire. Sapphire or Quartz is used because of its good heat resistanceand good optical characteristic as described later. However, the rod isnot limited to the sapphire or quartz. Since the rod has a good heatresistance, there is no need to provide a cooling arrangement to coolthe rod, which contributes miniaturization of the apparatus.

The rod can contain the heat radiation light incident thereon, andguides the heat radiation light to the casing with less attenuation.Accordingly, the rod has a superior light gathering efficiency.Additionally, the rod 210 enables a multiple reflection of the radiationlight between a high-reflectance surface of the chopper and the targetobject W. The temperature of the target object W can be accuratelymeasured by positioning the rod close to the object W to be processed.

The rod enables separation of the casing from the object W to beprocessed. Thus, the rod can omit a cooling arrangement to cool thecasing, and contributes to miniaturization of the heat treatmentapparatus. If the cooling arrangement to cool the casing is provided,the rod can minimize a power supplied to the cooling arrangement of therod.

The rod according to the present embodiment can be made of quartz orsapphire with a multi-core optical fiber. In such a case, the multi-coreoptical fiber is provided between the quartz or sapphire rod and thechopper. Thereby, the rod is provided with flexibility, which increasesa freedom in positioning the radiation thermometer 200. Additionally,since a main body or the casing 220 of the radiation thermometer 200 canbe separated from the object W to be processed, each part of theradiation thermometer 200 is prevented from being deformed sue toinfluence of the temperature of the object W to be processed, therebymaintaining an accurate measurement of the temperature of the object Wto be processed.

The casing has a substantially cylindrical shape, and is provided on thebottom part 114 so as to cover the through hole 115.

The chopper has a disk-like shape, and is positioned vertically so thata part of the chopper 230 is positioned under the through hole withinthe casing. The chopper is connected to a rotation axis of the motor atthe center thereof so as to be rotated by the motor. The surface of thechopper is divided into four equal parts including two high-reflectancesurfaces and two low-reflectance surfaces. The surfaces arealternatively arranged, and each of the surfaces has a slit. Thehigh-reflectance surfaces are formed, for example, by aluminum or goldplating. The low-reflectance surfaces are formed, for example, by blackpainting. Each of the high-reflectance surfaces has a measurement areacorresponding to the slit and a measurement area other than the slit.Similarly, each of the low-reflectance surfaces has a measurement areacorresponding to the slit and a measurement area 234 b other than theslit.

For example, the chopper may have a semicircular high-reflectancesurface with the slit. Alternatively, the chopper may be divided intofour or six equal parts with the high-reflectance surface with the slitsand notch portions arranged alternately. The slit may be provided onlyto the high-reflectance surfaces.

When the chopper is rotated by the motor, the high-reflectance surfaceand the low-reflectance surface alternately appear under the rod. Whenthe high-reflectance surface is positioned under the rod, a large par ofthe light propagated through the rod is reflected by thehigh-reflectance surface, and propagates again through the rod andprojected onto the object W to be processed. On the other hand, when thelow-reflectance surface is positioned under the rod, a large part of thelight propagates through the rod is absorbed by the low-reflectancesurface. Thus, a very small amount of light is reflected by thelow-reflectance surface. The slits guide the radiation light from theobject W to be processed or multi-reflected light to the detector.

The detector comprises an image forming lens (not shown in the figure),Si-photocell and amplification circuit. The radiation light incident onthe image forming lens is supplied to the control unit 300 afterconverting into an electric signal representing radiation intensitiesE₁(T) and E₂(T) as described later. The control unit 300 has a CPU and amemory so as to calculate the emissivity ε and the temperature T of thetarget object W in accordance with the radiation intensities E₁(T) andE₂(T). It should be noted that the calculation can be performed by anarithmetic unit (not shown in the figure) of the radiation thermometer200.

More specifically, the light passed through the slit is gathered by thelens, and is transmitted to the detector by the optical fiber. Theradiation intensities at the high-reflectance surface and thelow-reflectance surface are represented by the following equations (5)and (6), respectively.E ₁(T)=εE _(BB)(T)/[1−R(1−ε)]  (5)Where, E₁(T) is a radiation intensity of the high-reflectance surface atthe temperature T obtained by the detector; R is an effectivereflectance of the high-reflectance surface; ε is a reflectance of theobject W to be processed; and E_(BB)(T) is a radiation intensity of ablack body at the temperature T. The equation (5) is obtained by thefollowing equation (6). It is assumed that the object W to be processedhad no heat radiation.E ₁(T)=εE _(BB)(T)+εR(1−ε)E _(BB)(T)+ε[R(1−ε)]2+ . . . ∞=E_(BB)(T)/[1−R(1−ε)]  (6)E ₂(T)=εE _(BB)(T)  (7)

Where, E₂(T) is a radiation intensity of the low-reflectance surface atthe temperature T obtained by the detector. The equation (7) is obtainedfrom the prank Planck's law. The emissivity ε is represented by thefollowing equation (8).ε=[E ₂(T)/E ₁(T)+R−1]/R  (8)

Generally, spectral concentration of a radiant emittance of anelectromagnetic wave radiated by a black body can be given by the prankPlanck's law. When the radiation thermometer 200 measures a temperatureof a black body, the relationship between the temperature T of the blackbody and the radiation intensity E_(BB)(T) can be represented by thefollowing equation (9) and (10) by using constants A, B and C which aredetermined by an optical system of the radiation thermometer 200.E _(BB)(T)=Cexp[−C ₂/(AT+B)]  (9)T=C ₂ /A[InC−InE _(BB)(T)]−B/A  (10)

Where, C₂ is a second constant of radiation.

The detector or the control unit 300 can obtain the radiation intensityE_(BB)(T), and thereby the temperature T can be obtained by entering theradiation intensity E_(BB)(T) in the equation (7). Thus, the controlunit 300 can obtain the temperature T of the object W to be processed.

The operation of the entire heat treatment apparatus according to thepresent embodiment is the same as the heat treatment apparatusesaccording the above-mentioned first and second embodiments, anddescriptions thereof will be omitted.

The present invention is not limited to the specifically disclosedembodiments, and variations and modifications may be made withoutdeparting from the scope of the present invention.

The present application is base on Japanese priority applications No.2001-08266 filed on Mar. 2, 2001, No. 2001-059296 filed on Mar. 2, 2001,No. 2001-071548 filed on Mar. 14, 2001 and No. 2001-072317 filed on Mar.14, 2001, the entire contents of which are hereby incorporated byreference.

1. A lamp applicable to a heat source for heating an object to beprocessed, the lamp comprising: an electrode part to which an electricpower is supplied; a pair of first filaments connected to said electrodepart; and a second filament connected to said first filaments and havinga diameter smaller than a diameter of each of said first filaments,wherein said second filament is configured and arranged to serve as asurface illuminant with respect to the object to be processed, andwherein said surface illuminant has a convex shape protruding in adirection away from the object to be processed.
 2. A lamp applicable toa heat source for heating an object to be processed, the lampcomprising: an electrode part to which an electric power is supplied; apair of first filaments connected to said electrode part; a secondfilament connected to said first filaments and having a diameter smallerthan a diameter of each of said first filaments; and a shield part thatreflects a light emitted by said second filament, the shield part beinglocated on a side opposite to the object to be processed with respect tosaid second filament, wherein said second filament is configured andarranged to serve as a surface illuminant with respect to the object tobe processed.
 3. The lamp as claimed in claim 2, wherein said surfaceilluminant is parallel to the object to be processed.
 4. The lamp asclaimed in claim 2, wherein said surface illuminant has a polygonalshape or a circular shape when viewed from the object to be processed.5. A lamp applicable to a heat source for heating an object to beprocessed, the lamp comprising: an electrode part to which an electricpower is supplied; a pair of first filaments connected to said electrodepart; and a second filament connected to said first filaments and havinga diameter smaller than a diameter of each of said first filaments,wherein said second filament is configured and arranged to serve as asurface illuminant with respect to the object to be processed, andwherein said second filament includes a first part facing the object tobe processed and a second part farther from the object to be processedthan said first part, and said first part has a work function lower thana work function of said second part.
 6. The lamp as claimed in claim 5,wherein said first part has a cover film formed on a material the sameas a material of said second part, the cover film made of a materialhaving a work function lower than a work function of the material ofsaid second part.
 7. The lamp as claimed in claim 6, wherein said secondpart is made of tungsten, and said cover film is made of thorium.
 8. Thelamp as claimed in claim 6, wherein said second part is made of amaterial selected from a group consisting of platinum, connel alloy,tungsten and nickel, and said cover film is made of a material selectedfrom a group consisting of barium oxide, strontium oxide and calciumoxide.
 9. A heat treatment apparatus for applying a heat treatment to anobject to be processed, the heat treatment apparatus comprising: asupport member on which the object to be processed is placed; and aplurality of lamps located above said support member for heating theobject to be processed, each of said lamps comprising: an electrode partto which an electric power is supplied; a pair of first filamentsconnected to said electrode part; a second filament connected to saidfirst filaments and having a diameter smaller than a diameter of each ofsaid first; and a shield part that reflects a light emitted by saidsecond filament, the shield part being located on a side opposite to theobject to be processed with respect to said second filament, whereinsaid second filament is configured and arranged to serve as a surfaceilluminant with respect to the object to be processed.